Wells, M., Holdsworth, D. and McCann, A. P., "The Eldon 2 operating system for KDF9." pp21 - 24.

(1971) The Computer Journal 14(1) 1971  

Languages mentioned Kidsgrove Algol {1963} Usercode {1963} Autocode for the KDF9 Whetstone Algol {1964}