--- a/inst/encode.m
+++ b/inst/encode.m
@@ -36,30 +36,34 @@
 ## variable is a string taking one of the values
 ##
 ## @table @code
-## @item 'linear' or 'linear/binary'
+## @item  "linear"
+## @itemx "linear/binary"
 ## A linear block code is assumed with the coded message @var{code} being in
 ## a binary format. In this case the argument @var{opt} is the generator
 ## matrix, and is required.
-## @item 'cyclic' or 'cyclic/binary'
+## @item  "cyclic"
+## @itemx "cyclic/binary"
 ## A cyclic code is assumed with the coded message @var{code} being in a
 ## binary format. The generator polynomial to use can be defined in @var{opt}.
 ## The default generator polynomial to use will be
 ## @code{cyclpoly (@var{n}, @var{k})}
-## @item 'hamming' or 'hamming/binary'
+## @item  "hamming"
+## @itemx "hamming/binary"
 ## A Hamming code is assumed with the coded message @var{code} being in a
 ## binary format. In this case @var{n} must be of an integer of the form
 ## @code{2^@var{m}-1}, where @var{m} is an integer. In addition @var{k}
 ## must be @code{@var{n}-@var{m}}. The primitive polynomial to use can
 ## be defined in @var{opt}. The default primitive polynomial to use is
 ## the same as defined by @code{hammgen}.
-## @item 'bch' or 'bch/binary'
+## @item  "bch"
+## @itemx "bch/binary"
 ## A BCH code is assumed with the coded message @var{code} being in a binary
 ## format. The generator polynomial to use can be defined in @var{opt}.
 ## The default generator polynomial to use will be
 ## @code{bchpoly (@var{n}, @var{k})}
 ## @end table
 ##
-## In addition the argument 'binary' above can be replaced with 'decimal',
+## In addition the argument "binary" above can be replaced with "decimal",
 ## in which case the message is assumed to be a decimal vector, with each
 ## value representing a symbol to be coded. The binary format can be in two
 ## forms
@@ -80,7 +84,7 @@
 ## it is often faster to create a generator matrix externally with the
 ## functions @code{hammgen} or @code{cyclgen}, rather than let @code{encode}
 ## recalculate this matrix at each iteration. In this case @var{typ} should
-## be 'linear'. The exception to this case is BCH codes, whose encoder
+## be "linear". The exception to this case is BCH codes, whose encoder
 ## is implemented directly from the polynomial and is significantly faster.
 ##
 ## @seealso{decode, cyclgen, cyclpoly, hammgen, bchenco, bchpoly}
@@ -189,7 +193,7 @@
     else
       m = log2 (n + 1);
       if ((m != floor (m)) || (m < 3) || (m > 16))
-        error ("encode: codeword length must be of the form '2^m-1' with integer m");
+        error ("encode: codeword length must be of the form 2^m-1 with integer m");
       endif
       if (k != (n-m))
         error ("encode: illegal message length for hamming code");