The Latest Update to http://www.cpm8680.com/ includes the following 
(excellent) reference:

CP/M   Programmer's Reference Guide

From: Paul Schlyter
Subject: Re: Apple// CP/M question
Newsgroups: comp.sys.apple2
Date: 2000/11/15

http://www.cpm8680.com/CPMPRG.TXT

This may be of some interest to Apple CP/M users.  The first part is a 
reference to standard CP/M-80 (up to ver 2.2) and the second part is a 
reference of Apple (SoftCard) CP/M specific details, including BIOS details 
and some utility program details.

This document should be required reading for newbies like yours truly and is 
copied from the ever-increasing files section of:

Willi Kusche's Apple CP/M Group on Yahoo:

http://tech.groups.yahoo.com/group/applecpm/

YippeeKiyoKiyay!

Bill
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