Millar, The Emperor in the Roman World, 31 BC ? AD 337 (London: Duckworth, 1977), 6 and passim. See also: idem. "Emperors at Work", Journal of Roman Studies
Epirus: The Acheron Necromanteion: Ephyra-Pandosia-Coassope (Athens, 1973); idem, in: The Princeton Encyclopedia of Classical Sites (1976), pp. 310f. s.v
Saint-Pétersbourg, tome I, pp. 76–109 (1902) Bibliographie de la flore de Sibérie, idem, Saint-Pétersbourg, tome V (1909) Traces de la période post-glaciaire steppique