Artwork Images:
Literature:
Museo Guggenheim Bilbao. “Soto. The Fourth dimension”. Catalogue published on the occasion of the exhibition with the same title. 18 Oct 2019 – 9 Feb 2020. Illustrated in color, page 140-141.
“Soto” Ministerio de Cultura / Dirección General de Bellas Artes, Archivos y Biblotecas, Soto. Madrid, 1982, pag 129.
