diff --git a/Data/XML/DTD/Types.hs b/Data/XML/DTD/Types.hs
--- a/Data/XML/DTD/Types.hs
+++ b/Data/XML/DTD/Types.hs
@@ -43,22 +43,23 @@
     DTD (..)
   , DTDTextDecl (..)
   , DTDComponent (..)
-	
+
     -- * Entity declarations and references
   , EntityDecl (..)
-  , PEContent (..)
+  , EntityValue (..)
   , PERef
 
     -- * Element declarations
   , ElementDecl (..)
+  , ContentDecl (..)
   , ContentModel (..)
   , Repeat (..)
 
     -- * Attribute declarations
-  , AttrList (..)
-  , AttrDecl (..)
-  , AttrType (..)
-  , AttrDefault (..)
+  , AttList (..)
+  , AttDecl (..)
+  , AttType (..)
+  , AttDefault (..)
 
     -- * Notation declarations
   , Notation (..)
@@ -96,7 +97,7 @@
 data DTDComponent =
      DTDEntityDecl EntityDecl   -- ^ Entity declaration
    | DTDElementDecl ElementDecl -- ^ Element declaration
-   | DTDAttrList AttrList       -- ^ List of attribute declarions for
+   | DTDAttList AttList        -- ^ List of attribute declarions for
                                 -- an element
    | DTDNotation Notation       -- ^ A notation declaration
    | DTDPERef PERef             -- ^ A parameter entity reference in
@@ -115,39 +116,41 @@
 -- the DTD; it is specified by external syntax declared as a notation
 -- elsewhere in the DTD.
 data EntityDecl =
-     InternalEntityDecl
+     InternalGeneralEntityDecl
        { entityDeclName :: Text
-       , entityDeclValue :: Text
-       }                                  -- ^ An internal general entity
-   | ExternalEntityDecl
+       , entityDeclValue :: [EntityValue]
+       }
+   | ExternalGeneralEntityDecl
        { entityDeclName :: Text
        , entityDeclID :: ExternalID
        , entityDeclNotation :: Maybe Text
        }                                  -- ^ An external general
-                                          -- entity, parsed or
-                                          -- unparsed. It is unparsed
-                                          -- if a notation is
-                                          -- specified.
-
-   | ParameterEntityDecl
+                                          -- entity is unparsed if a
+                                          -- notation is specified.
+   | InternalParameterEntityDecl
        { entityDeclName :: Text
-       , peDeclValue :: [PEContent]
-       }                                 -- ^ A parameter entity
+       , entityDeclValue :: [EntityValue]
+       }
+   | ExternalParameterEntityDecl
+       { entityDeclName :: Text
+       , entityDeclID :: ExternalID
+       }
   deriving (Show, Eq)
 
 instance Typeable EntityDecl where
   typeOf = typeString "EntityDecl"
 
--- | Parameter entities need to be recursively resolved, so we
--- represent their content as a mixture of nested parameter entity
--- references and free text.
-data PEContent =
-     PEText Text
-   | PENested PERef
+-- | The value of an internal entity may contain references to
+-- parameter entities; these references need to be resolved to obtain
+-- the actual replacement value of the entity. So we represent the
+-- value as a mixture of parameter entity references and free text.
+data EntityValue =
+     EntityText Text
+   | EntityPERef PERef
   deriving (Show, Eq)
 
-instance Typeable PEContent where
-  typeOf = typeString "PEContent"
+instance Typeable EntityValue where
+  typeOf = typeString "EntityValue"
 
 -- | A parameter entity reference. It contains the name of the
 -- parameter entity that is being referenced.
@@ -194,61 +197,61 @@
   typeOf = typeString "Repeat"
 
 -- | A list of attribute declarations for an element.
-data AttrList =
-     AttrList
-       { attrListElementName :: Text -- ^ The name of the element to
-                                     -- which the attribute
-                                     -- declarations apply
-       , attrListDecls :: [AttrDecl]
+data AttList =
+     AttList
+       { attListElementName :: Text -- ^ The name of the element to
+                                    -- which the attribute
+                                    -- declarations apply
+       , attListDecls :: [AttDecl]
        }
   deriving (Show, Eq)
 
-instance Typeable AttrList where
-  typeOf = typeString "AttrList"
+instance Typeable AttList where
+  typeOf = typeString "AttList"
 
 -- | A declaration of an attribute that can occur in an element.
-data AttrDecl =
-     AttrDecl
-       { attrDeclName :: Text           -- ^ The name of the attribute
-       , attrDeclType :: AttrType       -- ^ The type of the attribute
-       , attrDeclDefault :: AttrDefault -- ^ The default value specification
+data AttDecl =
+     AttDecl
+       { attDeclName :: Text           -- ^ The name of the attribute
+       , attDeclType :: AttType        -- ^ The type of the attribute
+       , attDeclDefault :: AttDefault  -- ^ The default value specification
        }
   deriving (Show, Eq)
 
-instance Typeable AttrDecl where
-  typeOf = typeString "AttrDecl"
+instance Typeable AttDecl where
+  typeOf = typeString "AttDecl"
 
 -- | The type of value that an attribute can take.
-data AttrType =
-     AttrStringType           -- ^ Any text
-   | AttrIDType               -- ^ A unique ID
-   | AttrIDRefType            -- ^ A reference to an ID
-   | AttrIDRefsType           -- ^ One or more references to IDs
-   | AttrEntityType           -- ^ An unparsed external entity
-   | AttrEntitiesType         -- ^ One or more unparsed external entities
-   | AttrNmTokenType          -- ^ A name-like token
-   | AttrNmTokensType         -- ^ One or more name-like tokens
-   | AttrEnumType [Text]      -- ^ One of the given values
-   | AttrNotationType [Text]  -- ^ Specified by external syntax
-                              -- declared as a notation
+data AttType =
+     AttStringType           -- ^ Any text
+   | AttIDType               -- ^ A unique ID
+   | AttIDRefType            -- ^ A reference to an ID
+   | AttIDRefsType           -- ^ One or more references to IDs
+   | AttEntityType           -- ^ An unparsed external entity
+   | AttEntitiesType         -- ^ One or more unparsed external entities
+   | AttNmTokenType          -- ^ A name-like token
+   | AttNmTokensType         -- ^ One or more name-like tokens
+   | AttEnumType [Text]      -- ^ One of the given values
+   | AttNotationType [Text]  -- ^ Specified by external syntax
+                             -- declared as a notation
   deriving (Show, Eq)
 
-instance Typeable AttrType where
-  typeOf = typeString "AttrType"
+instance Typeable AttType where
+  typeOf = typeString "AttType"
 
 -- | A default value specification for an attribute.
-data AttrDefault =
-     AttrRequired          -- ^ No default value; the attribute must always
-                           -- be supplied
-   | AttrImplied           -- ^ No default value; the attribute is optional
-   | AttrFixed Text        -- ^ When supplied, the attribute must have the
-                           -- given value
-   | AttrDefaultValue Text -- ^ The attribute has the given default value
-                           -- when not supplied
+data AttDefault =
+     AttRequired          -- ^ No default value; the attribute must always
+                          -- be supplied
+   | AttImplied           -- ^ No default value; the attribute is optional
+   | AttFixed Text        -- ^ When supplied, the attribute must have the
+                          -- given value
+   | AttDefaultValue Text -- ^ The attribute has the given default value
+                          -- when not supplied
   deriving (Show, Eq)
 
-instance Typeable AttrDefault where
-  typeOf = typeString "AttrDefault"
+instance Typeable AttDefault where
+  typeOf = typeString "AttDefault"
 
 -- | A declaration of a notation.
 data Notation =
diff --git a/dtd-types.cabal b/dtd-types.cabal
--- a/dtd-types.cabal
+++ b/dtd-types.cabal
@@ -1,5 +1,5 @@
 name: dtd-types
-version: 0.2.0.1
+version: 0.3.0.1
 synopsis: Basic types for representing XML DTDs
 description:
   This package provides types to represent an XML Document Type