P. Arndt and W. Amelung, Photographische Einzelaufnahmen antiker Sculpturen, Munich, 1893, nos. 3902-3.
Antiken aus rheinischem Privatbesitz, Rheinischen Landesmuseum, Bonn, 1973-1974, pp. 211-212, no. 352, pl. 159.
This head is from a known group of Hellenistic portraits of Alexander the Great from Egypt, and all approximately one third life-size. This one appears to have been gilded judging from the dark brown patches with remains of gold leaf above eyebrow and on hair.
For a full discussion of this head and its place in the Alexander portrait iconography, see Nikolaus Himmelmann's catalogue entry in the above publication Antiken aus rheinischem Privatbesitz.
For a similar terracotta head of Alexander, cf. Dr. D. Wildung and Prof. dr. G. Grimm, Götter Pharaonen, exhibition catalogue, Mainz, 1978, no. 77.