Article date: Apr 1977
Article title: The pool-table triangle, a limerick paradox and divers other challenges
Mathematical Games column? Y
Book: 13. Penrose Tiles to Trapdoor Ciphers
Chapter: 9. Pool-Ball Triangles and Other Problems
This data confirmed? yes
Notes
Peter Rowlett (27 August 2022):
Peter Rowlett initial guess (Uncertain)
Peter Rowlett (4 November 2023):
I have seen this chapter and column side-by-side and they match.