References for the outgroup issue

[KARN at Butler.EDU]

Dear Netters,
	If this seems like deja vu, I'm sending it again because my system
said it didn't go through the first time.
	I caught the tail-end of the electronic debate on outgroups (ca. June?) and was wondering if there was a reference(s) to the issue in the literature.
Given the liveliness of the discussion, I hope that someone has aired it in 
print.  Please send any references that address the subject or impinge on it
, even if only tangentially.
Thanks,
Bob Karn
KARN at BUTLERU.EDU