Typographical Errors

page 51, lines 16-17:

The initial back quote in the first regular expression and the last square bracket in the second regular expression are missing from "For example, `[[a -> b], b, x y z] denotes the same relation as [a -> [x | y | z]]." (Thanks to Violetta Cavalli-Sforza.)

page 400, line 10 from the bottom:  The first line has "krb" instead of "ktb". (Thanks to Shlomo Yona.)

Upper:   prefixes   ktb   CaCaC   suffixes
Lower:   prefixes     katab       suffixes