The monuments of Aksum : an illustrated account ; based on the work in A.D. 1906 of the Deutsche Aksum-Expedition by Enno Littmann, Daniel Krencker and Theodor von Lüpke (Berlin 1913) and including previously unpublished photographs from the Staatsbibliothek zu Berlin - Phillipson, D. W.; Littmann, Enno, 1875-1958; Krencker, Daniel M. 1874-1941; Lüpke, Th. von (Addis Ababa University Press ; British Inst. in Eastern Africa, 1997)