1 mail art : handwritten, ill. ; 28 x 22 cm. (letter); 11 x 24 cm. (envelope)
Includes a one-page letter in which Caldera writes about planning his next visit to New York, and his adjustment to a new job, and three artistamp sheets, one of which includes photos of himself (labeled with his correspondence art name, "Creative Thing") and John Held, Jr.
Archives of American Art, Smithsonian Institution Washington, D.C. 20560