I recommend this article for its history of the death certificate and for its discussion of certificates' limitations. I think online access to it at The New Yorker site is for subscribers only, but maybe the article will eventually be available in various online archives. DEPT. OF PUBLIC HEALTH FINAL FORMS What death certificates can tell us, and what they can’t. BY KATHRYN SCHULZ The New Yorker, APRIL 7, 2014. PJ