In the interest of full disclosure (or maybe it's second or third level bragging rights), (/me reddens) TheSource User's Manual (well, its brown, thick, three-ring binder which has, admittedly, been re-purposed) still holds a place on the shelves above my router (a device of which few of us even dreamed when TheSource was in business)... as does my beloved (and much tattered) Z80 Assembly Language Programming, Leventhal, et al.
... and in a further admission of guilt, I failed in my efforts to find links with pictures of documentation for my PDP-11... or of its GIGUNDO, IMMENSE, HUGE 5 !!!! Meg HD with removable 10-inch platters (that drew nearly 20 amps on startup)... or it's 1-inch tape drive (recording, IIRC, at about the same pace as data flowed thru a 300 baud modem) until, much belatedly, I stumbled upon this from M$, yet!
Of course, that one deals with the 11-10 and 11-20... but there is a readily recognizable DEC logo on the cover.