Elizabeth (Burr) (Clark) Church

I still use the LDS databases of IGI and Ancestral File for clues, but, of course, never cite to them nor believe them.  Generally speaking if I find a date, such as the death date of Elizabeth (Burr) (Clark) Church as 24 February 1764, I believe it is probably true.  Most people don't make up such exact dates out of whole cloth.  My job is to find the good source where that information actually comes from.  In this case, I'm having a devil of a time locating it.  Was it in Hartford, Bolton, Ct. or Bolton, Ma.?  Is it a gravestone, death or burial record?  Vital record, probate, or church record?  I'm still searching.  If you know where this information comes from, please call me.