Onstott, Tullis Cullen (1981). Paleomagnetism of the Guayana Shield, Venezuela and its implications concerning Proterozoic tectonics of South America and Africa (Ph.D. thesis). Princeton University. OCLC46407032. ProQuest303126269.
Onstott, Tullis Cullen (1981). Paleomagnetism of the Guayana Shield, Venezuela and its implications concerning Proterozoic tectonics of South America and Africa (Ph.D. thesis). Princeton University. OCLC46407032. ProQuest303126269.