From 'Writers At Work' (Secker & Warburg, 1968), which is a collection of Paris Review interviews. Burroughs went to St. Louis late in 1964 on assignment for Playboy, which rejected his piece. The wonderfully-named Conrad Knickerbocker conducted the interview for Paris Review whilst he was there. When it was published in '65 it included one page from his journal, apparently, but this book has three. I couldn't find these online so I thought I'd scan them.