The Roots of SGML: A Personal Recollection
http://www.ingentaconnect.com/content/stc/tc/1999/00000046/00000001/art00008
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  peer-reviewed

Goldfarb, Charles F.
Technical Communication Online
1999

Abstract:

One of the inventors of the markup language that evolved into Standard Generalized Markup Language describes the origins of SGML and provides an anecdotal history of markup language development from the late 1960s to the 1980s.