I found the reference
Axiomatic charge conjugation, J. Math. Phys. (to appear)
in W. F. Eberlein, Models of space-time, Bull. Amer. Math. Soc. 71 (1965), 731-736, (pdf) however, I don't find the referenced paper anywhere. In 1965, Eberlein was working at the University of Rochester. Does anybody know anything about that paper?