Phillips de Pury & Luxembourg, New York, "20-21st Century Design," New York, June 11, 2003, lot 130
Literature
Nancy N. Schiffer and Val O. Bertoia, The World of Bertoia, Atglen, 2003, pp. 178-179, 188, 191-193, 201, 208-210, 218, 220, 223-224 for similar examples