Glinert, E. P. and McIntyre, D. W. "The Design and Implementation of SunPict, a User Extensible Visual Environment for Intermediate Scale Procedural Programming"

Salvendy, G. (1989) Salvendy, G. and M.J. Smith, (ed) Proc. Third Intl. Conf. on Human-Computer Interaction (HCI'89), Boston, September 18-22, 1989  

Languages mentioned Pict/D {1984} Interactive graphical programming environment