1. Goldsteine H. H., and J. von. Neumann, 在为U.S. Army Ordinance Department, 1947; 所提交的报告中“Planning and coding problems for en electronic computing instrument,” Part II, Vol. 1.; 并在 J. von. Neumann, “Collected Works,”中重新发表 A. H. Taub (ed.). Vol. v., New York: Macmillan. P. 80-151.
2. Private communication, 1957. 该观点在Iverson, K. E., “The use of APL in Teaching,” Yorktown, N.Y.: IBM Corp., 1969中提出.
3. PL/I的另外一个例子由B. Walter and M. Bohl, 在“From better to best - tips for good programming,” Software Age, 3, 11(Nov., 1969), pp. 46-50中提出. 相同的技术可以使用在Algol中, 甚至还有一个Fortran格式的程序”STYLE”来达到上述效果. 参见D. D. McCracken, and G. M. Weinberg, “How to write a readable FORTRAN program,” Datamation, 18, 10(Oct., 1972), pp. 73-77.
