Programming Language for Automata. - Donald E. Knuth; Richard H. Bigelow (J. ACM, 1967)

Specialized languages: an applications methodology. - Richard H. Bigelow; Norton R. Greenfield; Peter Szolovits; Frederick B. Thompson (AFIPS National Computer Conference, 1973)

The REL animated film language. - Frederick B. Thompson; Richard H. Bigelow; Norton Greenfeld; J. Odden; D. Reece; Peter Szolovits (SIGGRAPH, 1974)