S. A. Brown , C. E. Drayton , B. Mittman, "A description of the APT language"

[ACM] (1963) [ACM] CACM 6(11) (Nov 1963)  

Languages mentioned APT {1956} Automatically Programmed Tools APT II {1958} Automatically Programmed Tools v2 APT III {1961} Automatically Programmed Tools v3