Survey of Viable ALGOL 68 Implementations (AB52.3.1 in Algol Bulletin 52)
(1985)
Languages mentioned
ALGOL 68C
{1975} Cambridge Algol 68
ALGOL 68RS
{1972} Extended RS Algol
ALGOL 68S
{1977} Simplified version of ALGOL 68
FLACC
{1977} Mailloux's Algol 68