Can anyone provide me with a reference to one or more of the standard Pali grammars to support footnotes in translations from both Horner and Warder (separately) to the effect that the vocative masculine plural of a personal name may be used when addressing a group that includes the individual whose name occurs in the plural. I'd also be curious to know if this usage of the vocative plural is acceptable in Classical Sanskrit.
I'm travelling at the moment, so I don't have access to the grammars I would normally consult. Duroiselle (on-line version) gives both a and aa for the mas. sing., as does Bhikkhu Nyanatusita's declension table, but I wonder if this is a misunderstanding of the distinctive use of the plural of a personal name reported by both Horner and Warder.