A Qianlong marked example in the National Palace Museum, Taibei, is illustrated in the Catalogue, Blue and White Wares of the Ch'ing Dynasty, Book II, pl 21.
This shape is recorded by Geng Bao Chang, Ming Qiing Ciqi Zhidian, fig. 50, no. 14
A pair of Daoguang marked ewers was sold in our Hong Kong Rooms, 09 September 1989, lot 787.
The Chinese University of Hong Kong, Imperial Porcelain of Late Qing, Kwan Collection, 1983, Catalogue, no. 5
National Museum of History, Taipei, Imperial Porcelain of late Ch'ing, From the Kwan Collection, 1985, Catalogue, no. 5