Wilkes, M. V. "PUFS--A Programmer's Utility Filing System" pp107-116.

Information Processing Machines: Proceedings of th (1965) Information Processing Machines: Proceedings of the Symposium held in Prague on September 7th-9th, 1964. Czechislovak Academy of Sciences (Prague) and Iliffe Books, Ltd. (London) 1965  

Languages mentioned PUFS {1963} NPL for files