Lucas, Peter "Requirements On A Language For Logical Data Processing" p556-560

Popplewell, Cicely M. (1962) Popplewell, Cicely M. (Ed.) Information Processing 62, Proceedings of the 2nd IFIP Congress, Munich, Aug. 1962. North Holland Publ. Co., 1963.  

Languages mentioned LOGALGOL {1960} Set-based ALGOL variant from IBM Vienna