The 1968 Sackman, Erikson & Grant paper is available as a scanned PDF, btw:
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD0645438&Locati...
The 1968 Sackman, Erikson & Grant paper is available as a scanned PDF, btw:
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD0645438&Locati...