Page 126

Location: Chapter 12, solution to Problem 11

It is (last sentence)

Hence C(HR) -- or alternatively R(HR)R -- is a warbler.

It should become

Hence C(H(CC))=C(HR) -- or alternatively R(HR)R -- is a warbler.

Short explanation

The added expression, while equivalent by virtue of R=CC, is the natural one that is encountered during the derivation hence is quite helpful if made explicit.