[30]对 Stulen 和 Brogren 的访谈。
[31]对 Parsons 的访谈；John T. Parsons,“Preliminary Report on Digitron,”August 29, 1952 (typescript); John T. Parsons, “The Digitron Story," 1955(typescript), Parsons, diary notes; L. V. Colwell to John T. Parsons (re: Lockheed proposal) , August 12, 1948, Parsons files; Lockheed Aircraft Corporation, wing panel drawing, PD 903 — 02, July 30, 1948, Parsons files; Parsons Industries, “Cardamatic Milling,” promotional brochure; “Faster Diemaking,” Business Week, November 6, 1948, p. 70。 (The same page which announced Parsons's idea also carried an advertisement by the Haloid Company of Rochester, New York, announcing its new line of products called “xerox".)
[32] “Faster Diemaking," Business Week , November 6, 1948, p. 70; American Machinist, November 1977, pp. G—3, 6.
[33]对 Patsons 的访谈，其信件及私人文件；“Faster Diemaking”。
[34] 1948 年 8 月 31 日研究和开发局的 L. R. Hafsted 与 John T. Parsons 的谈话，Parsons 的私人文件；“Cardamatic Milling”；“Faster Diemaking”; letters of inquiry, Par-sons files.
[35]美国空军与帕森斯公司的合同，编号为AF 33(038）6878，“Design，Con-struction, and Installation of an Automatic Contour Cutting Machine,”June 1949。不幸的是，现在已经不可能从美国空军的角度来重建数值控制的历史。根据俄亥俄州Wright-Patterson空军基地的空军装备司令部的档案记载，所有有关空军数值控制工程的记录(从该合同起多达10年)，都已经被销毁。
[36]1978 年和 1979 年对 Stulen 和 Parsons 的访谈；Parsons 的日记。
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