The circular necklace closing device is similar to one, also carved with a coiled bird, excavated from Tomb No. 9 at Zhuyuan'gou, Baoji, Shaanxi province, illustrated by Gu Fang, The Complete Collection of Jades Unearthed in China, vol. 14, Beijing, 2005, p. 54. Two others in the Sonnenschein Collection, are illustrated by S. Salmony, Archaic Chinese Jades, The Art Institute of Chicago, 1952, pl. LXII (2 and 4).