Alan Kay wrote:
> 
> The story about Smalltalk-72 is in "The Early History of Smalltalk"
> that I wrote for ACM's "History of Programming Languages" in 93. I
> have a pdf file which I'll put on an FTP server somewhere. Also, Dan
> wrote a truly great paper a few years after Smalltalk-72 about
> Smalltalk-76, a little of which I included in the "History". However,
> you should read this as well. I think it was for POPL 78, and there
> is probably an online copy somewhere ....

http://users.ipa.net/~dwighth/smalltalk/St76/Smalltalk76ProgrammingSystem.html