It looks like you have to be an ACM member to access these, but all the papers are online for HOPL II: http://dl.acm.org/citation.cfm?id=234286 http://dl.acm.or

It looks like you have to be an ACM member to access these, but all the papers are online for HOPL II: http://dl.acm.org/citation.cfm?id=234286 http://dl.acm.org/citation.cfm?id=234286 HOPL III is here: http://dl.acm.org/citation.cfm?id=1238844&coll=DL&dl=GUIDE&CFID=530866641&CFTOKEN=40970330 http://dl.acm.org/citation.cfm?id=1238844&coll=DL&dl=GUIDE&C... HOPL I is here: http://dl.acm.org/citation.cfm?id=800025&coll=DL&dl=GUIDE&CFID=530866641&CFTOKEN=40970330 http://dl.acm.org/citation.cfm?id=800025&coll=DL&dl=GUIDE&CF... I have the hardcopy versions of I and II that I bought used from Amazon and they're great.