Source : Free On-Line Dictionary of Computing

FGL
     
        1. Flow Graph Lisp.  A distributed dataflow language for AMPS
        (Applicative Multi-Processing System).  "A Loosely-Coupled
        Applicative Multi-Processing System", R. Keller et al, NCC,
        AFIPS June 1979, pp.613- 622.
     
        2. Function Graph Language.  Related to FEL.