Axel Salto, Den Spirende Stil, Copenhagen, 1949, pp. 92-93 for images and and a drawing of other examples in the 'Sprouting' style
Forces of Nature: Axel Salto: Ceramics & Drawings, exh. cat., Antik, New York, 1999, pp. 2, 9 for other examples in the 'Sprouting' style