For specifying graphic operations. ["A ProblEM Oriented Graphic Language", P.J. Schwinn, proc ACM 22nd Natl Conf, 1967]. [Sammet 1969, p. 677].

In addition suitable contents:
[ 2 ] [ ACM ] [ ag ] [ am ] [ an ] [ at ] [ b ] [ C ] [ ch ] [ ci ] [ CM ] [ ec ] [ ed ] [ er ] [ era ] [ et ] [ G ] [ ge ] [ gr ] [ graph ] [ gu ] [ h ] [ ie ] [ in ] [ io ] [ J ] [ M ] [ mm ] [ N ] [ nf ] [ ng ] [ nn ] [ ns ] [ O ] [ op ] [ pe ] [ ph ] [ pr ] [ ro ] [ S ] [ spec ] [ ua ] [ win ]