Chester Yellowhair Navajo Silversmith 1930's to 1980's

I have been trying to find an example of his work and what his hallmark looks like. I can’t find a thing and I have looked in nearly every book published about Navajo Silversmiths. He is identified as an important contributor but there should be examples somewhere. I would appreciate any input on where I might find this information. Thank you.

Do you know what area he is from and where did you read he was an important contributor? Thanks for sharing