Philip José Farmer posited that earlier in his extended lifetime, long before visiting Barsoom or America, John Carter had been Norman of Torn. In Tarzan Alive Farmer noted that Norman was an ancestor of Tarzan.
Later, Peter Coogan, has suggested that John Carter is identifiable Phra the Phoenician. This character appears in The Wonderful Adventures of Phra the Phoenician (1890) edited by Edwin L. Arnold. Dr. Coogan has expanded upon these theories in conjunction with Dennis Power, in doing so identifying evidence that Carter's "nephew" could not have been Edgar Rice Burroughs himself, and was in fact Carter's own son - Matthew Nicholas Carter.
- Wikipedia article on John Carter of Mars
- The Tarzan/John Carter/Pellucidar/Caspak/Moon/Carson of Venus Chronology
- John Carter is Phra the Phoenician! by Peter Coogan
- John Carter, Torn from Phoenician Dreams (part one) by Dennis E. Power and Peter Coogan
- John Carter, Torn from Phoenician Dreams (part two) by Dennis E. Power and Peter Coogan
- The Carters of Virginia (This article posits that John Carter is also related to detective Nick Carter and occult investigator Randolph Carter as well as others)
- The Life of Matthew Nicholas Carter
- Excerpt from THE ARMS OF TARZAN (on Norman of Torn and John Carter of Mars) by Philip José Farmer