[R] Formal definitions of R-language.

[M.Kondrin]

Hello!
Some CS-guys (the type who knows what Church formalism is) keep asking 
me questions about formal definitions of R-language that I can not 
answer (or even understand). Is there some freely available papers which 
I can throw at them where it would be explained is R 
functional/OOP/procedural language, does it use weak/strong, 
dynamic/static typization, does it use lazy or ...(do not know what) 
evaluation, what sort of garbage collector it uses?
Thanks.