S. Ornstein, M. Stucki, and W. Clark. AFIPS Spring Joint Computing Conference, volume 30 of AFIPS Conference Proceedings, page 337-355. AFIPS / ACM / Thomson Book Company, Washington D.C., (1967)
W. Clark. AFIPS Spring Joint Computing Conference, volume 30 of AFIPS Conference Proceedings, page 335-336. AFIPS / ACM / Thomson Book Company, Washington D.C., (1967)