Books on Gemini G.E.L.

Gemini G.E.L.: Art and Collaboration, author Ruth E. Fine, publishers National Gallery of Art, Washington DC and Abbeville Press, New York. ISBN 0-89659-506-4
Artists at Gemini G.E.L.: Celebrating the 25th Year, author Mark Rosenthal, publisher Harry N. Abrams, Inc., New York. 
Gemini G.E.L.: Recent Prints and Sculpture, author Charles Ritchie (with an introduction by Ruth E. Fine), publisher National Gallery of Art, Washington DC.