Etta Peterson
发表
Keith A. Kvenvolden,
Edward Bunnenberg,
Cyril Ponnamperuma,
1971
.
W. A. Payne,
William V. Boynton,
Paul W. Hodge,
1973
.
Keith A. Kvenvolden,
Edward Bunnenberg,
Cyril Ponnamperuma,
1970
.