diff --git a/music-pitch.cabal b/music-pitch.cabal
--- a/music-pitch.cabal
+++ b/music-pitch.cabal
@@ -1,15 +1,15 @@
 
-name:               music-pitch
-version:            1.6
-cabal-version:      >= 1.10
-author:             Hans Hoglund
-maintainer:         Hans Hoglund
-license:            BSD3
-license-file:       COPYING
-synopsis:           Abstract representation of musical pitch.
-category:           Music
-tested-with:        GHC
-build-type:         Simple
+name:                   music-pitch
+version:                1.6.1
+cabal-version:          >= 1.10
+author:                 Hans Hoglund
+maintainer:             Hans Hoglund
+license:                BSD3
+license-file:           COPYING
+synopsis:               Abstract representation of musical pitch.
+category:               Music
+tested-with:            GHC
+build-type:             Simple
 
 description: 
     This package provides various representations of musical pitch.
@@ -23,32 +23,28 @@
     <http://music-suite.github.io>.
 
 source-repository head
-  type:             git
-  location:         git://github.com/music-suite/music-pitch.git
+  type:                 git
+  location:             git://github.com/music-suite/music-pitch.git
   
 library                    
-    build-depends: 
-        base                    >= 4 && < 5,
-        time,
-        random,
-        containers,
-        semigroups,
-        semigroupoids,
-        music-pitch-literal     == 1.6,
-        vector-space
-
-    hs-source-dirs: src
-    default-language: Haskell2010
-    exposed-modules:
-        Music.Pitch
-        Music.Pitch.Absolute
-        Music.Pitch.Alterable
-        Music.Pitch.Augmentable
-        Music.Pitch.Common
-        Music.Pitch.Common.Interval
-        Music.Pitch.Common.Pitch
-        Music.Pitch.Common.Semitones
-        Music.Pitch.Common.Spell
-        Music.Pitch.Common.Harmony
-        Music.Pitch.Intonation
-    other-modules:
+    build-depends:      base                    >= 4 && < 5,
+                        time,
+                        random,
+                        containers,
+                        semigroups,
+                        semigroupoids,
+                        music-pitch-literal     == 1.6,
+                        vector-space
+    exposed-modules:    Music.Pitch
+                        Music.Pitch.Absolute
+                        Music.Pitch.Common
+                        Music.Pitch.Common.Interval
+                        Music.Pitch.Common.Pitch
+                        Music.Pitch.Common.Semitones
+                        Music.Pitch.Common.Spell
+                        Music.Pitch.Common.Harmony
+                        Music.Pitch.Koizumi
+                        Music.Pitch.Tokawa
+                        Music.Pitch.Intonation
+    hs-source-dirs:     src
+    default-language:   Haskell2010
diff --git a/src/Music/Pitch.hs b/src/Music/Pitch.hs
--- a/src/Music/Pitch.hs
+++ b/src/Music/Pitch.hs
@@ -36,7 +36,7 @@
 
         -- -- | Pitch and intervals, as defined in Common Music Theory (CMT).
         -- --
-        -- --   Includes representation of common practice pitches and intervalssuch as /c sharp/, 
+        -- --   Includes representation of common practice pitches and intervals such as /c sharp/, 
         -- --   /diminished second/ and so on.
         module Music.Pitch.Common,
         
diff --git a/src/Music/Pitch/Alterable.hs b/src/Music/Pitch/Alterable.hs
deleted file mode 100644
--- a/src/Music/Pitch/Alterable.hs
+++ /dev/null
@@ -1,56 +0,0 @@
-
-{-# LANGUAGE GeneralizedNewtypeDeriving, StandaloneDeriving #-}
-
-------------------------------------------------------------------------------------
--- |
--- Copyright   : (c) Hans Hoglund 2012
---
--- License     : BSD-style
---
--- Maintainer  : hans@hanshoglund.se
--- Stability   : experimental
--- Portability : non-portable (TF,GNTD)
---
--------------------------------------------------------------------------------------
-
-module Music.Pitch.Alterable (
-        -- * Alterable class
-        Alterable(..),
-  ) where
-
-import Data.Ratio
-
--- |
--- Class of things that can be altered.
---
--- > accidental (sharpen a) = sharpen (accidental a)
--- > accidental (flatten a) = flatten (accidental a)
--- > sharpen . flatten      = id
---
-class Alterable a where
-    -- | 
-    -- Increase the given pitch by one.
-    -- 
-    sharpen :: a -> a
-
-    -- | 
-    -- Decrease the given pitch by one.
-    -- 
-    flatten :: a -> a
-
-
-instance Alterable a => Alterable (b -> a) where
-    sharpen = fmap sharpen
-    flatten = fmap flatten
-
-instance Alterable Double where
-    sharpen = (+ 1)
-    flatten = (subtract 1)
-
-instance Alterable Integer where
-    sharpen = (+ 1)
-    flatten = (subtract 1)
-
-instance Integral a => Alterable (Ratio a) where
-    sharpen = (+ 1)
-    flatten = (subtract 1)
diff --git a/src/Music/Pitch/Augmentable.hs b/src/Music/Pitch/Augmentable.hs
deleted file mode 100644
--- a/src/Music/Pitch/Augmentable.hs
+++ /dev/null
@@ -1,52 +0,0 @@
-
-{-# LANGUAGE GeneralizedNewtypeDeriving, StandaloneDeriving #-}
-
-------------------------------------------------------------------------------------
--- |
--- Copyright   : (c) Hans Hoglund 2012
---
--- License     : BSD-style
---
--- Maintainer  : hans@hanshoglund.se
--- Stability   : experimental
--- Portability : non-portable (TF,GNTD)
---
--------------------------------------------------------------------------------------
-
-module Music.Pitch.Augmentable (
-        -- * Augmentable class
-        Augmentable(..),
-  ) where
-
-import Data.Ratio
-
--- |
--- Class of types that can be augmented.
---
--- > quality (augment a)  = augment (quality a)
--- > quality (diminish a) = diminish (quality a)
--- > augment . diminish   = id
---
-class Augmentable a where
-
-    -- | 
-    -- Increase the size of this interval by one.
-    --
-    augment :: a -> a
-
-    -- | 
-    -- Decrease the size of this interval by one.
-    --
-    diminish :: a -> a
-
-instance Augmentable Double where
-    augment  = (+ 1)
-    diminish = (subtract 1)
-
-instance Augmentable Integer where
-    augment  = (+ 1)
-    diminish = (subtract 1)
-
-instance Integral a => Augmentable (Ratio a) where
-    augment  = (+ 1)
-    diminish = (subtract 1)
diff --git a/src/Music/Pitch/Common.hs b/src/Music/Pitch/Common.hs
--- a/src/Music/Pitch/Common.hs
+++ b/src/Music/Pitch/Common.hs
@@ -14,126 +14,130 @@
 -------------------------------------------------------------------------------------
 
 module Music.Pitch.Common (
-    -- * Enharmonic representation
-    -- ** Octaves
-    Octaves,
-    HasOctaves(..),
-
-    -- ** Steps
-    Steps,
-    HasSteps(..),
-
-    -- ** Semitones
-    Semitones,
-    HasSemitones(..),
-    semitone,
-    tone,
-    ditone,
-    tritone,
-    isSemitone,
-    isTone,
-    isTritone,
-    
-    -- ** Enharmonic equivalence
-    (=:=),
-    (/:=),
-
-    -- * Pitches
-    -- ** Name type
-    Name(..),
-
-    -- ** Accidental  type
-    Accidental,
-    doubleFlat, 
-    flat, 
-    natural, 
-    sharp, 
-    doubleSharp,
-
-    -- *** Inspecting accidentals
-    isNatural,
-    isSharpened,
-    isFlattened,
-    isStandard,
-
-    -- ** Pitch type
-    Pitch,    
-    pitch,
-    name,
-    accidental,
-    asPitch,
-
-    -- module Music.Pitch.Common.Name,
-    -- module Music.Pitch.Common.Accidental,
-    -- module Music.Pitch.Common.Pitch,
-
-    -- * Intervals
-    -- ** Number type
-    Number,
-    HasNumber(..),   
-    unison,
-    prime,
-    second,
-    third,
-    fourth,
-    fifth,
-    sixth,
-    seventh,
-    octave,
-    ninth,
-    tenth,
-    twelfth, 
-    duodecim,
-    thirteenth,
-    fourteenth,
-    fifteenth,
-
-    -- ** Quality type
-    Quality(..),    
-    HasQuality(..),
-    invertQuality,
-    isPerfect,
-    isMajor,
-    isMinor,
-    isAugmented,
-    isDiminished,
-
-    -- ** Interval type
-    Interval,
-
-    -- *** Creating intervals
-    interval,
-    perfect,
-    major,
-    minor,
-    augmented,
-    diminished,
-    doublyAugmented,
-    doublyDiminished,
-    asInterval,
-
-    -- *** Inspecting intervals
-    isNegative,
-    isPositive,
-    isNonNegative,
-    isPerfectUnison,
-    isStep,
-    isLeap,
-
-    -- *** Simple and compound intervals
-    isSimple,
-    isCompound,
-    separate,
-    simple,
+    -- -- * Enharmonic representation
+    -- -- ** Octaves
+    -- Octaves,
+    -- -- HasOctaves(..),
+    -- 
+    -- -- ** Steps
+    -- -- Steps,
+    -- -- HasSteps(..),
+    -- 
+    -- -- ** Semitones
+    -- Semitones,
+    -- HasSemitones(..),
+    -- semitone,
+    -- tone,
+    -- ditone,
+    -- tritone,
+    -- isSemitone,
+    -- isTone,
+    -- isTritone,
+    -- 
+    -- -- ** Enharmonic equivalence
+    -- (=:=),
+    -- (/:=),
+    -- 
+    -- -- * Pitches
+    -- -- ** Name type
+    -- Name(..),
+    -- 
+    -- -- ** Accidental  type
+    -- Accidental,
+    -- doubleFlat, 
+    -- flat, 
+    -- natural, 
+    -- sharp, 
+    -- doubleSharp,
+    -- 
+    -- -- *** Inspecting accidentals
+    -- isNatural,
+    -- isSharpened,
+    -- isFlattened,
+    -- isStandard,
+    -- 
+    -- -- ** Pitch type
+    -- Pitch,    
+    -- pitch,
+    -- name,
+    -- accidental,
+    -- asPitch,
+    -- 
+    -- -- module Music.Pitch.Common.Name,
+    -- -- module Music.Pitch.Common.Accidental,
+    -- -- module Music.Pitch.Common.Pitch,
+    -- 
+    -- -- * Intervals
+    -- -- ** Number type
+    -- Number,
+    -- HasNumber(..),   
+    -- unison,
+    -- prime,
+    -- second,
+    -- third,
+    -- fourth,
+    -- fifth,
+    -- sixth,
+    -- seventh,
+    -- octave,
+    -- ninth,
+    -- tenth,
+    -- twelfth, 
+    -- duodecim,
+    -- thirteenth,
+    -- fourteenth,
+    -- fifteenth,
+    -- 
+    -- -- ** Quality type
+    -- Quality(..),    
+    -- HasQuality(..),
+    -- invertQuality,
+    -- isPerfect,
+    -- isMajor,
+    -- isMinor,
+    -- isAugmented,
+    -- isDiminished,
+    -- 
+    -- -- ** Interval type
+    -- Interval,
+    -- 
+    -- -- *** Creating intervals
+    -- interval,
+    -- perfect,
+    -- major,
+    -- minor,
+    -- augmented,
+    -- diminished,
+    -- doublyAugmented,
+    -- doublyDiminished,
+    -- asInterval,
+    -- 
+    -- -- *** Inspecting intervals
+    -- isNegative,
+    -- isPositive,
+    -- isNonNegative,
+    -- isPerfectUnison,
+    -- isStep,
+    -- isLeap,
+    -- 
+    -- -- *** Simple and compound intervals
+    -- isSimple,
+    -- isCompound,
+    -- separate,
+    -- octaves,
+    -- simple,
+    -- 
+    -- -- *** Inversion
+    -- invert,  
 
-    -- *** Inversion
-    invert,
+    -- * Enharmonic representation
+    module Music.Pitch.Common.Semitones,
 
-    -- module Music.Pitch.Common.Number,
-    -- module Music.Pitch.Common.Quality,
-    -- module Music.Pitch.Common.Interval,
+    -- * Non-enharmonic representation
+    module Music.Pitch.Common.Interval,
+    module Music.Pitch.Common.Pitch,
 
-    -- * Miscellaneous
+    -- * Utility
     module Music.Pitch.Common.Spell,
     module Music.Pitch.Common.Harmony,
 )
diff --git a/src/Music/Pitch/Common/Harmony.hs b/src/Music/Pitch/Common/Harmony.hs
--- a/src/Music/Pitch/Common/Harmony.hs
+++ b/src/Music/Pitch/Common/Harmony.hs
@@ -15,6 +15,13 @@
 import Data.Set (Set)
 import qualified Data.Set as Set
 
+{-
+  TODO
+  Generalize simple like this:
+    > (number (asInterval (m9))-(fromIntegral $ signum (m9))) `mod` 7
+    
+-}
+
 -- | Whether the given interval is a (harmonic) dissonance.
 isDissonance :: Interval -> Bool
 isDissonance x = case number (simple x) of
diff --git a/src/Music/Pitch/Common/Interval.hs b/src/Music/Pitch/Common/Interval.hs
--- a/src/Music/Pitch/Common/Interval.hs
+++ b/src/Music/Pitch/Common/Interval.hs
@@ -51,7 +51,7 @@
         Interval,
 
         -- *** Creating intervals
-        interval,
+        mkInterval,
         perfect,
         major,
         minor,
@@ -61,6 +61,7 @@
         doublyDiminished,
 
         -- *** Inspecting intervals
+        octaves,
         isNegative,
         isPositive,
         isNonNegative,
@@ -80,7 +81,7 @@
         -- * Utility
         asInterval,
         intervalDiff,
-        interval',
+        mkInterval',
   ) where
 
 import Data.Maybe
@@ -244,73 +245,73 @@
 instance Show Number where { show = show . getNumber }
 instance HasNumber Number where number = id
 
-unison      :: Number
-prime       :: Number
-second      :: Number
-third       :: Number
-fourth      :: Number
-fifth       :: Number
-sixth       :: Number
-seventh     :: Number
-octave      :: Number
-ninth       :: Number
-tenth       :: Number
-eleventh    :: Number
-twelfth     :: Number
-duodecim    :: Number
-thirteenth  :: Number
-fourteenth  :: Number
-fifteenth   :: Number
 
 -- | A synonym for @1@.
+unison      :: Number
 unison      = 1
 
 -- | A synonym for @2@.
+prime       :: Number
 prime       = 1
 
 -- | A synonym for @3@.
+second      :: Number
 second      = 2
 
 -- | A synonym for @4@.
+third       :: Number
 third       = 3
 
 -- | A synonym for @5@.
+fourth      :: Number
 fourth      = 4     
 
 -- | A synonym for @6@.
+fifth       :: Number
 fifth       = 5
 
 -- | A synonym for @7@.
+sixth       :: Number
 sixth       = 6
 
 -- | A synonym for @8@.
+seventh     :: Number
 seventh     = 7
 
 -- | A synonym for @9@.
+octave      :: Number
 octave      = 8
 
 -- | A synonym for @10@.
+ninth       :: Number
 ninth       = 9
 
 -- | A synonym for @11@.
+tenth       :: Number
 tenth       = 10
 
 -- | A synonym for @12@.
+eleventh    :: Number
 eleventh    = 11
 
 -- | A synonym for @13@.
+twelfth     :: Number
 twelfth     = 12
 
 -- | A synonym for @14@.
+duodecim    :: Number
 duodecim    = 12
 
 -- | A synonym for @15@.
+thirteenth  :: Number
 thirteenth  = 13
 
 -- | A synonym for @16@.
+fourteenth  :: Number
 fourteenth  = 14
 
 -- | A synonym for @17@.
+fifteenth   :: Number
 fifteenth   = 15
 
 class HasNumber a where
@@ -430,15 +431,16 @@
     augment  (Interval (o, d, c)) = Interval (o, d, c + 1)
     diminish (Interval (o, d, c)) = Interval (o, d, c - 1)
 
-instance HasOctaves Interval where
-    octaves = fst . separate
+-- |
+-- Returns the non-simple part of an interval.
+--
+-- > (perfect octave)^*x + y = z  iff  y = simple z
+--
+octaves = fst . separate
 
 instance HasSemitones Interval where
     semitones (Interval (o, d, c)) = fromIntegral $ o * 12 + c
 
-instance HasSteps Interval where
-    steps a = fromIntegral $ semitones a `mod` 12
-
 instance IsInterval Interval where
     fromInterval (IntervalL (o,d,c)) = Interval (fromIntegral o, fromIntegral d, fromIntegral c)
 
@@ -455,40 +457,46 @@
 -- major interval instead. Given 'Major' or 'Minor' with a number indicating a perfect
 -- consonance, 'interval' returns a perfect or diminished interval respectively.
 --
-interval :: Quality -> Number -> Interval
-interval quality number = interval' (qualityToDiff (isPerfectNumber diatonic) quality) (fromIntegral number)
+mkInterval :: Quality -> Number -> Interval
+mkInterval quality number = mkInterval' (qualityToDiff (isPerfectNumber diatonic) quality) (fromIntegral number)
     where
         (_, diatonic) = (fromIntegral $ number - 1) `divMod` 7
 
-interval' :: Int -> Int -> Interval
-interval' diff number = Interval (octave, diatonic, diatonicToChromatic diatonic + diff)
+mkInterval' :: Int -> Int -> Interval
+mkInterval' diff number = Interval (octave, diatonic, diatonicToChromatic diatonic + diff)
     where
         (octave, diatonic) = (number - 1) `divMod` 7
 
-
 -- | Creates a perfect interval.
 --   If given an inperfect number, constructs a major interval.
-perfect = interval Perfect
+perfect :: Number -> Interval
+perfect = mkInterval Perfect
 
 -- | Creates a major interval.
 --   If given a perfect number, constructs a perfect interval.
-major = interval Major
+major :: Number -> Interval
+major = mkInterval Major
 
 -- | Creates a minor interval.
 --   If given a perfect number, constructs a diminished interval.
-minor = interval Minor
+minor :: Number -> Interval
+minor = mkInterval Minor
 
 -- | Creates an augmented interval.
-augmented  = interval (Augmented 1)
+augmented :: Number -> Interval
+augmented  = mkInterval (Augmented 1)
 
 -- | Creates a diminished interval.
-diminished = interval (Diminished 1)
+diminished :: Number -> Interval
+diminished = mkInterval (Diminished 1)
 
 -- | Creates a doubly augmented interval.
-doublyAugmented  = interval (Augmented 2)
+doublyAugmented :: Number -> Interval
+doublyAugmented  = mkInterval (Augmented 2)
 
 -- | Creates a doubly diminished interval.
-doublyDiminished = interval (Diminished 2)
+doublyDiminished :: Number -> Interval
+doublyDiminished = mkInterval (Diminished 2)
 
 
 invertDiatonic :: Num a => a -> a
@@ -631,6 +639,6 @@
         go 6 = 11
 
 {-# DEPRECATED intervalDiff "This should be hidden" #-}
-{-# DEPRECATED interval'    "This should be hidden "#-}
+{-# DEPRECATED mkInterval'  "This should be hidden "#-}
 
 replicate' n = replicate (fromIntegral n)
diff --git a/src/Music/Pitch/Common/Pitch.hs b/src/Music/Pitch/Common/Pitch.hs
--- a/src/Music/Pitch/Common/Pitch.hs
+++ b/src/Music/Pitch/Common/Pitch.hs
@@ -19,16 +19,16 @@
 module Music.Pitch.Common.Pitch (
         -- * Accidentals
         Accidental,
-        doubleFlat, 
-        flat, 
         natural, 
+        flat, 
         sharp, 
+        doubleFlat, 
         doubleSharp,
 
         -- ** Inspecting accidentals
         isNatural,
-        isSharpened,
         isFlattened,
+        isSharpened,
         isStandard,
 
         -- ** Name
@@ -36,11 +36,10 @@
 
         -- * Pitch
         Pitch,    
-        pitch,
+        mkPitch,
         name,
         accidental,
-        asPitch,
-        middleC,
+        asPitch
   ) where
 
 import Data.Maybe
@@ -65,7 +64,7 @@
 -- An accidental is either flat, natural or sharp.
 --
 -- This representation allows for an arbitrary number of flats or sharps rather than just
--- single (the ♯ and ♭ symbols) and double (i.e. the /x/ and ♭♭ symbols).
+-- single and double.
 --
 -- The 'Num' and 'Enum' instances treat 'Accidental' as the number of altered semitones, 
 -- i.e. a double flat is @-2@, natural @0@ and so on.
@@ -88,11 +87,11 @@
 
 -- | 
 -- Magic instance that allow us to write @c sharp@ instead of @sharpen c@.
--- Requires @FlexibleInstances@.
 --
 instance (IsPitch a, Alterable a) => IsPitch (Accidental -> a) where
     fromPitch l 1       = sharpen (fromPitch l)
     fromPitch l (-1)    = flatten (fromPitch l)
+-- Requires FlexibleInstances
 
 sharp, flat, natural, doubleFlat, doubleSharp :: Accidental
 
@@ -124,7 +123,7 @@
 
 
 -- | Returns whether this is a standard accidental, i.e.
---   either a double flat, flat, natural, sharp or doubl sharp.
+--   either a double flat, flat, natural, sharp or double sharp.
 isStandard :: Accidental -> Bool
 isStandard a = abs a < 2
 
@@ -222,8 +221,8 @@
 -- |
 -- Creates a pitch from name accidental.
 --
-pitch :: Name -> Accidental -> Pitch
-pitch name acc = Pitch $ interval' (fromIntegral acc) (fromEnum name + 1)
+mkPitch :: Name -> Accidental -> Pitch
+mkPitch name acc = Pitch $ mkInterval' (fromIntegral acc) (fromEnum name + 1)
 
 -- |
 -- Returns the name of a pitch.
@@ -231,7 +230,9 @@
 -- To convert a pitch to a numeric type, use 'octaves', 'steps' or 'semitones'
 -- on the relevant interval type, for example:
 --
--- @ semitones (a' .-. 'middleC') @
+-- @
+-- semitones ('a\'' .-. 'c')
+-- @
 --
 name :: Pitch -> Name
 name = toEnum . fromIntegral . pred . number . simple . getPitch
@@ -244,15 +245,6 @@
 accidental :: Pitch -> Accidental
 accidental = fromIntegral . intervalDiff . simple . getPitch
 
--- instance HasOctaves Pitch where
---     octaves = octaves . getPitch
--- 
--- instance HasSemitones Pitch where
---     semitones = semitones . getPitch
--- 
--- instance HasSteps Pitch where
---     steps = steps . getPitch
-
 -- | The same as 'c', but fixed to 'Pitch'. This is useful if you want
 --   to treat 'Pitch' as an affine space around middle C, that is /C4/ in Scientific Pitch Notation.
 middleC :: Pitch
@@ -260,9 +252,9 @@
 
 instance IsPitch Pitch where
     fromPitch (PitchL (c, a, o)) =
-        Pitch $ interval' (qual a) (c + 1)
+        Pitch $ mkInterval' (qual a) (c + 1)
             ^+^
-            (perfect octave^* fromIntegral (o - 4))
+            (perfect octave^* fromIntegral o)
         where
             qual Nothing  = 0
             qual (Just n) = round n
diff --git a/src/Music/Pitch/Common/Semitones.hs b/src/Music/Pitch/Common/Semitones.hs
--- a/src/Music/Pitch/Common/Semitones.hs
+++ b/src/Music/Pitch/Common/Semitones.hs
@@ -19,11 +19,11 @@
         -- * Types
         -- ** Octaves
         Octaves,
-        HasOctaves(..),
+        -- HasOctaves(..),
 
         -- ** Steps
         Steps,
-        HasSteps(..),
+        -- HasSteps(..),
 
         -- ** Semitones
         Semitones,
@@ -84,8 +84,9 @@
     deriving (Eq, Ord, Num, Enum, Real, Integral)
 
 instance Show     Steps where { show = show . getSteps }
-instance HasSteps Steps where { steps = id }
+-- instance HasSteps Steps where { steps = id }
 
+{-
 -- |
 -- Class of intervals that has a number of 'Steps'.
 --
@@ -100,6 +101,7 @@
     -- > octaves (-m7)             =  -1
     --
     steps :: a -> Steps
+-}
 
 
 
diff --git a/src/Music/Pitch/Common/Spell.hs b/src/Music/Pitch/Common/Spell.hs
--- a/src/Music/Pitch/Common/Spell.hs
+++ b/src/Music/Pitch/Common/Spell.hs
@@ -23,12 +23,12 @@
         -- * Spelling type
         Spelling,
         spell,
-        spelledWith,
+        spelled,
         
         -- ** Standard spellings
-        modal,
-        sharps,
-        flats,
+        modally,
+        usingSharps,
+        usingFlats,
   ) where
 
 import Data.VectorSpace
@@ -69,9 +69,9 @@
 --
 -- Examples:
 --
--- > spell sharps tritone   == _A4
--- > spell flats  tritone   == d5
--- > spell modal  tone      == _M2
+-- > spell usingSharps tritone   == _A4
+-- > spell usingFlats  tritone   == d5
+-- > spell modally     tone      == _M2
 --
 type Spelling = Semitones -> Number
 
@@ -85,7 +85,7 @@
     (octaves, steps) = semitones x `divMod` 12
     num  = fromIntegral (spelling steps)
     diff = fromIntegral steps - fromIntegral (diatonicToChromatic num)
-    in interval' diff (num + 1) ^+^ _P8^*(fromIntegral octaves)
+    in mkInterval' diff (num + 1) ^+^ _P8^*(fromIntegral octaves)
     where
         diatonicToChromatic = go
             where
@@ -100,21 +100,21 @@
 -- |
 -- Flipped version of 'spell'. To be used infix, as in:
 --
--- > d5 `spelledWith` sharps
+-- > d5 `spelled` usingSharps
 --        
-spelledWith :: HasSemitones a => a -> Spelling -> Interval
-spelledWith = flip spell
+spelled :: HasSemitones a => a -> Spelling -> Interval
+spelled = flip spell
 
 -- |
 -- Spell using the most the most common accidentals. Double sharps and flats are not
 -- preserved.
 --
--- This spelling is particularly useful for modal music with C or F as tonic.
+-- This spelling is particularly useful for modal music where the tonic is C.
 --
 -- > c cs d eb e f fs g gs a bb b
 --
-modal :: Spelling
-modal = go
+modally :: Spelling
+modally = go
     where
         go 0  = 0
         go 1  = 0
@@ -134,8 +134,8 @@
 --
 -- > c cs d ds e f fs g gs a as b
 --
-sharps :: Spelling
-sharps = go
+usingSharps :: Spelling
+usingSharps = go
     where
         go 0  = 0
         go 1  = 0
@@ -155,8 +155,8 @@
 --
 -- > c db d eb e f gb g ab a bb b
 --
-flats :: Spelling
-flats = go
+usingFlats :: Spelling
+usingFlats = go
     where
         go 0  = 0
         go 1  = 1
diff --git a/src/Music/Pitch/Koizumi.hs b/src/Music/Pitch/Koizumi.hs
new file mode 100644
--- /dev/null
+++ b/src/Music/Pitch/Koizumi.hs
@@ -0,0 +1,3 @@
+
+module Music.Pitch.Koizumi where
+
diff --git a/src/Music/Pitch/Tokawa.hs b/src/Music/Pitch/Tokawa.hs
new file mode 100644
--- /dev/null
+++ b/src/Music/Pitch/Tokawa.hs
@@ -0,0 +1,3 @@
+
+module Music.Pitch.Tokawa where
+