diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,12 @@
 
 # Changelog by versions
 
+## From 3.17.0.0 to 3.17.1.0
+
+* New math space commands (romildo).
+* New function: mapLaTeXT (ddssff).
+* Some fixes for qrcode package (L3n41c).
+
 ## From 3.16.2.0 to 3.17.0.0
 
 * New 'array' command (NorfairKing).
diff --git a/Examples/mathSpaces.hs b/Examples/mathSpaces.hs
new file mode 100644
--- /dev/null
+++ b/Examples/mathSpaces.hs
@@ -0,0 +1,23 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module Main where
+
+import Text.LaTeX
+import Text.LaTeX.Packages.AMSMath
+
+main :: IO ()
+main = execLaTeXT mathSpaces >>= renderFile "mathSpaces.tex"
+
+mathSpaces :: Monad m => LaTeXT_ m
+mathSpaces = do
+ documentclass [] article
+ usepackage [] amsmath
+ document $
+   tabular Nothing [RightColumn, LeftColumn] $ do
+     texttt "quad"       & math ("H" >> quad       >> "H") ; lnbk
+     texttt "qquad"      & math ("H" >> qquad      >> "H") ; lnbk
+     texttt "thinspace"  & math ("H" >> thinspace  >> "H") ; lnbk
+     texttt "medspace"   & math ("H" >> medspace   >> "H") ; lnbk
+     texttt "thickspace" & math ("H" >> thickspace >> "H") ; lnbk
+     texttt "negspace"   & math ("H" >> negspace   >> "H") ; lnbk
+     texttt "space"      & math ("H" >> space      >> "H")
diff --git a/HaTeX.cabal b/HaTeX.cabal
--- a/HaTeX.cabal
+++ b/HaTeX.cabal
@@ -1,5 +1,5 @@
 Name: HaTeX
-Version: 3.17.0.2
+Version: 3.17.1.0
 Author: Daniel Díaz
 Category: LaTeX
 Build-type: Simple
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -55,12 +55,11 @@
 
 There are many ways to get involved in the HaTeX project. Use the most comfortable way for you.
 
-* Fork the [GitHub repository](https://github.com/Daniel-Diaz/HaTeX).
+* Fork the [GitHub repository](https://github.com/Daniel-Diaz/HaTeX) and make your own contributions.
 * Report bugs or make suggestions opening a ticket in the [Issue Tracker](https://github.com/Daniel-Diaz/HaTeX/issues).
 * Help us to improve and extend our [hatex-guide](https://github.com/Daniel-Diaz/hatex-guide).
 * Join the [Mailing List](http://projects.haskell.org/cgi-bin/mailman/listinfo/hatex) for help or announcements of the
 latest developments.
-* Drop by the IRC channel at `#hatex`.
 
 ## TODO list
 
@@ -73,7 +72,9 @@
 * [haskintex](http://daniel-diaz.github.io/projects/haskintex): Tool to use Haskell (and, additionaly, the HaTeX library)
 within a LaTeX file.
 * [TeX-my-math](https://github.com/leftaroundabout/Symbolic-math-HaTeX): Experimental library to ease the production
-of mathematical expressions using HaTeX (_no longer maintained?_).
+of mathematical expressions using HaTeX.
+* [blatex](http://hackage.haskell.org/package/blatex): Static site generator for blogs where posts are written
+in LaTeX.
 
 ## Travis automatic build
 
diff --git a/Text/LaTeX/Base/Writer.hs b/Text/LaTeX/Base/Writer.hs
--- a/Text/LaTeX/Base/Writer.hs
+++ b/Text/LaTeX/Base/Writer.hs
@@ -48,6 +48,7 @@
  , rendertexM
  , liftFun
  , liftOp
+ , mapLaTeXT
    -- * Re-exports
  , lift
  , liftIO
@@ -189,6 +190,17 @@
  (p,l') <- lift $ runWriterT c'
  tell $ l `op` l'
  return p
+
+-- | A helper function for building monad transformers, e.g.
+-- @@
+--       instance MonadReader r m => MonadReader r (LaTeXT m) where
+--         ask = lift ask
+--         local = mapLaTeXT . local
+-- @@
+-- This declaration could be included here, but it would add a
+-- dependency on mtl.
+mapLaTeXT :: (m (a, LaTeX) -> m (a, LaTeX)) -> LaTeXT m a -> LaTeXT m a
+mapLaTeXT f = LaTeXT . mapWriterT f . unwrapLaTeXT
 
 -- | Just like 'rendertex', but with 'LaTeXT' output.
 --
diff --git a/Text/LaTeX/Packages/AMSMath.hs b/Text/LaTeX/Packages/AMSMath.hs
--- a/Text/LaTeX/Packages/AMSMath.hs
+++ b/Text/LaTeX/Packages/AMSMath.hs
@@ -119,6 +119,7 @@
  , v2matrix
    -- * Math spacing
  , quad, qquad
+ , thinspace, medspace, thickspace, negspace, space
    ) where
 
 import Text.LaTeX.Base
@@ -1055,14 +1056,22 @@
 qquad :: LaTeXC l => l
 qquad = comm0 "qquad"
 
-{-
-  The following commands are pending. Someone needs to find suitable
-  names for them.
+-- | \, space equal to 3/18 of \quad (= 3 mu)
+thinspace :: LaTeXC l => l
+thinspace = comm0 ","
 
-  \, 				3/18 of \quad (= 3 mu)
-  \: 				4/18 of \quad (= 4 mu)
-  \; 				5/18 of \quad (= 5 mu)
-  \! 				-3/18 of \quad (= -3 mu)
-  \ (space after backslash!) 	equivalent of space in normal text
+-- | \: space equal to 4/18 of \quad (= 4 mu)
+medspace :: LaTeXC l => l
+medspace = comm0 ":"
 
--}
+-- | \: space equal to 5/18 of \quad (= 5 mu)
+thickspace :: LaTeXC l => l
+thickspace = comm0 ";"
+
+-- | \! space equal to -3/18 of \quad (= -3 mu)
+negspace :: LaTeXC l => l
+negspace = comm0 "!"
+
+-- | \ (space after backslash) equivalent of space in normal text
+space :: LaTeXC l => l
+space = comm0 " "
diff --git a/Text/LaTeX/Packages/QRCode.hs b/Text/LaTeX/Packages/QRCode.hs
--- a/Text/LaTeX/Packages/QRCode.hs
+++ b/Text/LaTeX/Packages/QRCode.hs
@@ -21,7 +21,6 @@
 import Text.LaTeX.Base.Types
 import Text.LaTeX.Base.Texy
 import qualified Data.Text as T
-import Data.Char (toLower)
 
 -- | qrcode package. Use it to import it like this:
 --
@@ -57,7 +56,7 @@
 
 -- | This package option (which is the default) sets the qrcode package to generate print-quality QR codes.
 final :: LaTeXC l => l
-final = "draft"
+final = "final"
 
 -- | Generates a QR code with specified options and content.
 --
@@ -66,9 +65,9 @@
 qr :: LaTeXC l => CodeOptions -> Text -> l
 qr opt payload = fromLaTeX $ TeXComm "qrcode" [opts, FixArg . raw . escape $ payload]
   where
-    opts = MOptArg [ if includePadding opt then "padding" else "tight" 
-                   , if link opt then "link" else "nolink" 
-                   , texy . ("level=" <>) . T.singleton . toLower . head . show . errorLevel $ opt 
+    opts = MOptArg [ if includePadding opt then "padding" else "tight"
+                   , if link opt then "link" else "nolink"
+                   , texy . ("level=" <>) . T.singleton . head . show . errorLevel $ opt
                    ]
 
 -- Helper functions for escaping code contents.