Nick Caputo, via the GCD Error List (10 January 2005) suggested Larry Leiber for pencils and George Roussos ? for inks. The original index for the original presentation suggested Werner Roth ? for both.
Credits per Nick Caputo, Jan 2011, who believes the bulk of the art is by Brodsky & Roussos. Other possible assistants include Mike Esposito, John Tartaglione and John Romita.