Compare with a pair of cups in the Percival David Foundation, illustrated in Sekai toji zenshu, vol. 15, Japan, 1983, p. 203, no. 292, and another pair by R. Krahl, Chinese Ceramics from the Meiyintang Collection, vol. 2, London, 1994, p. 240, no. 908. One from a pair in the Baur Collection is illustrated with a matching saucer by J. Ayers in The Baur Collection, vol. III, Geneva, 1972, nos. A 489-492. See, also, a similar Yongzheng-marked cup illustrated by Peter Lam in Shimmering Colors, Monochromes of the Yuan to Qing Periods, The Zhu Yue Tang Collection, Art Museum, the Chinese University of Hong Kong, 2005, p. 209, no. 133.