His "big bertha" was (as I remember) in a book he authored and was published in the early fifties. I can't remember the title but the paper cover had a picture of a photographer holding a leica with an accessory viewfinder which was superimposed over his eyes (lens over the right and viewfinder over the left). My only suggestion for a starting point would be the Library of Congress.
This was one of the first books about photography that I read (and, hopefully, learned from).