Subroutines were implemented in [[Konrad Zuse]]'s [[Z4 (computer)|Z4]] in 1945.
In 1945, [[Alan M. Turing]] used the terms "bury" and "unbury" as a means of calling and returning from subroutines.<ref name="Turing_1945">{{citation |author-first=Alan Mathison |author-last=Turing |author-link=Alan Mathison Turing |title=Proposals for Development in the Mathematics Division of an Automatic Computing Engine (ACE) |date=1946-03-19 |orig-year=1945}} (NB. Presented on 1946-03-19 before the Executive Committee of the National Physical Laboratory (Great Britain).)</ref><ref name="Carpenter_1977">{{cite journal |title=The other Turing machine |author-last1=Carpenter |author-first1=Brian Edward |author-link1=Brian Carpenter (Internet engineer) |author-last2=Doran |author-first2=Robert William |author-link2=Robert William Doran |date=1977-01-01 |orig-year=October 1975 |doi=10.1093/comjnl/20.3.269 |volume=20 |issue=3 |journal=[[The Computer Journal]] |pages=269–279|doi-access=free }} (11 pages)</ref>
In January 1947 John Mauchly presented general notes at 'A Symposium of Large Scale Digital Calculating Machinery'
