IBM released it's 360 assembler language source code of Kenneth Iverson's APL language.

http://www.computerhistory.org/atchm...e-source-code/


I met Kenneth Iverson in Toronto when I was a student.
He had tremendous energy and generously gave me over an hour of his time, and two books on APL.

The descriptive and analytical power of an adequate programming language amply repays the considerable effort required for its mastery.
- Kenneth Iverson