Date of the Veda

[Edwin F Bryant]

I am doing research involving the antiquity of the Veda.  Can any one
refer me to sources, over the last century or more, that have contributed 
to establishing the commonly assigned date of circa 1200 BCE (apart from
Max Muller's assignment of 200 year periods for the various texts back 
dated from the beginning of the Buddhist period, which he later
acknowledged was totally arbitrary)? Is there any material that has
contested these dates (apart from Winternitz)?  Most especially, is there
any more recent material discussing the problems of Vedic dating (by which
I intend the whole corpus including Braahma.nas etc.)?  Any references at
all would be much appreciated.  Thank you.  Edwin Bryant  Columbia 
University.