1. R.A. Sibley. CACM 4(1):75-84 (Jan 1961).
2. Set LANGuage. Jastrzebowski, ca 1990. C extension with set-theoretic data types and garbage collection. "The SLANG Programming Language Reference Manual, Version 3.3", W. Jastrzebowski wojtek@loml.math.yale.edu , 1990.
3. Structured LANGuage. Michael Kessler, IBM. A language based on structured programming macros for IBM 370 assembly language. "Project RMAG: SLANG (Structured Language) Compiler", R.A. Magnuson, NIH-DCRT-DMB-SSS-UG105, NIH, DHEW, Bethesda, MD 20205 (1980).
4. "SLANG: A Problem Solving Language for Continuous-Model Simulation and Optimisation", J.M. Thames, Proc 24th ACM Natl Conf 1969.