diff --git a/src/intro/data-types.md b/src/intro/data-types.md
index d8b001b..b54241a 100644
--- a/src/intro/data-types.md
+++ b/src/intro/data-types.md
@@ -105,7 +105,7 @@ contain constructors that refer to the same data type. For example, a
 binary tree can be defined as follows.
 
 ```fram
-data Tree X =
+data rec Tree X =
   | Leaf
   | Node of Tree, X, Tree
 ```
@@ -204,9 +204,9 @@ sequence of definitions.
 ```fram
 data Vec3D T = Vec3D of { x : T, y : T, z : T }
 
-method x (Vec2D { x }) = x
-method y (Vec2D { y }) = y
-method z (Vec2D { z }) = z
+method x (Vec3D { x }) = x
+method y (Vec3D { y }) = y
+method z (Vec3D { z }) = z
 ```
 
 Therefore, records can be used in a similar way as records in other
diff --git a/src/ref/lexer.md b/src/ref/lexer.md
index 79ccaef..f4e32a1 100644
--- a/src/ref/lexer.md
+++ b/src/ref/lexer.md
@@ -3,8 +3,8 @@
 ## Whitespace
 
 The following characters are considered as whitespace (blanks): horizontal tab
-(`0x09`), new line (`0x10`), vertical tab (`0x11`), form feed (`0x12`),
-carriage return (`0x13`), and space (`0x20`). Whitespace characters are ignored
+(`0x09`), new line (`0xA`), vertical tab (`0xB`), form feed (`0xC`),
+carriage return (`0xD`), and space (`0x20`). Whitespace characters are ignored
 by the lexer, but they separate tokens, e.g., identifiers or literals.
 
 ## Comments