Item one: Lady Helena Carnegie (ed.), Catalogue of the collection of antique gems formed by James, Ninth Earl of Southesk, K.T., London, 1908, I, pp. 175-176, no. N55.
For a similar winged figure standing above Ouroboros, cf. S. Michel, Magische Gemmen, München, 2001, p. 37, no. 26 (item one); also see, B. Y. Berry, Ancient Gems from the Collection of Burton Y. Berry, Indiana University Art Museum, 1968, p. 87, no. 159, for figure of Harpocrates riding goose (item two).