The Free On-line Dictionary of Computing (30 December 2018):

SNOBOL3

   SNOBOL with user-defined functions.  Written in 1965.  The
   SNOBOL 6.3 compiler for the PDP-6 and PDP-10 was written
   in SNOBOL.

   ["The SNOBOL3 Programming Language", D.J. Farber et al, Bell
   Sys Tech J 45(6):895-944 (Jul 1966)].

   (1994-11-04)