Vincent M. Sarich
"Immunological time scale for hominid evolution"
Science 158, 1967, p. 1200-1203.
Sarich and Wilson's analysis of immunological evidence allowed them to propose "that if, man and Old World monkeys shared a common ancestor 30 million years ago, then man and apes shared a common ancestor no more than 5 million years ago, upsetting the contemporary view that human's common ancestor was Ramapithecus, a 13 million year old. This challenge to paleontological opinion purely on the basis of biochemistry of living species was for sometime either ridiculed or ignored, but is now fairly well accepted."