From: David Griffith
 Sent: Friday, February 26, 2016 4:05 PM
  One of my ongoing wish projects is to learn to
program a pdp-10 so I can
 port Frotz to it. 
 The canonical textbook is Ralph Gorin's _Introduction to DECSYSTEM-20
 Assembly Language Programming_ (Digital Press, 1981).  Lots of examples,
 well thought out presentation.
 
There is a similar document online at Columbia with parts written by Ralph Gorin
<http://www.columbia.edu/kermit/ftp/dec20/assembler-guide.txt>
John H. Reinhardt