PDP-11/20/15/r20 processor handbook.
APA Citation
Digital Equipment Corporation. (1971). PDP-11/20/15/r20 processor handbook. [Maynard, Mass.]: Digital Equipment Corporation.
MLA Citation
Digital Equipment Corporation. PDP-11/20/15/r20 Processor Handbook. [Maynard, Mass.]: Digital Equipment Corporation, 1971.
Warning: These citations may not always be complete (especially for serials).