Ogof Ffynnon Ddu, Penwyllt, Breconshire
By: by P.M. O'Reilly, S.E. O'Reilly, C.M. Fairbairn and members of South Wales Caving Club.
Contributors: O'Reilly, S. E.; Fairbairn, C. M.; South Wales Caving Club.
Publisher: South Wales Caving Club
Published: 1969
Place of publication: Swansea
Language: eng