Version of C used in 2.11 BSD Hi,

I'm playing with 2.11 BSD in SIMH, and I'm trying to write some programs for it using the c compiler that 2.11 BSD came with. There are some strange quirks that are definitely not C99, so I was following the text of K&amp;R's 1978 C. However, there are still some inconsistencies between K&amp;R C and the C that the compiler seems to be expecting. I guess my question is: what version of C was used in 2.11 BSD, and is there a good reference book for it?