Richard Pankhurst: Letter Writing and the Use of Royal and Imperial Seals in Ethiopia prior to the Twentieth Century. In: Journal of Ethiopian Studies. Band11, Nr.1, 1973, ISSN0304-2243, S.179–207, JSTOR:41988572.
Richard Pankhurst: Letter Writing and the Use of Royal and Imperial Seals in Ethiopia prior to the Twentieth Century. In: Journal of Ethiopian Studies. Band11, Nr.1, 1973, ISSN0304-2243, S.179–207, JSTOR:41988572.