Yes, the Knuth book is good, but note that what it is is a collection of papers, most of which are not really about literate programming. Some of them predate

Yes, the Knuth book is good, but note that what it is is a collection of papers, most of which are not really about literate programming. Some of them predate literate programming as such; e.g., there's a classic called "Structured programming with go to statements". There's the original article from 1984 that introduced literate programming. There are two "Programming Pearls" columns from CACM; the first is another introduction to literate programming, and the second is a not-entirely-trivial program for counting common words in a file -- followed by a review by Doug McIlroy which is very well worth reading in its own right. There are extracts from the TeX and METAFONT (literate) source code. There's the classic "The Errors of TeX" paper, as well as the whole TeX error log up to 1991. (And a few other things, but I think the ones I listed above are the most interesting.)