Compare the bubble bowls illustrated by J. Ayers in the Catalogue of the Baur Collection, Geneva, 1968, vol. 1, nos. A31 and A32; by S. Lee, Asian Art: Selections from the Collections of Mr. and Mrs. John D. Rockefeller 3rd, Part II, New York, 1975, p. 45, no. 28; by Liu Liang-Ju, A Survey of Chinese Ceramics: Sung Wares , Hong Kong, 1991, p. 125 (top); and in Song Dynasty Ceramics, Idemitsu Museum of Arts, Japan, 1979, no. 65.