The Ethiopic Liturgy: Its sources, Development and present form 1915

The Ethiopic Liturgy: Its sources, Development and present form, by Samuel Mercer, 1915

It includes text in Geez

القداس في الكنيسة الاثيوبيه : مصادره وتطوره وشكله الحالي ١٩١٥

http://www.coptic.org/language/ethiopicliturgyi00mercuoft.pdf
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According to the author, then:

The Ethiopic Church has been isolated from the rest of Christendom from the time of its foundation down to the present day with the exception of two comparatively short periods, namely, the first three hundred years of its existence (c. 340-650), and the period of Eoman missions (c. 1550-1632). Because of this isolation, the Ethiopic Church has produced no historians, and consequently European scholars have been given no materials with which to reconstruct the Church's history; with the result that there does not exist to-day a history of the Ethiopic Church worthy of the name.

Chronicles have at all times been kept by Abyssinian students and learned men, and a few copies of these are preserved in public and private libraries in Europe and America, and many of them exist in monasteries of the Ethiopic Church; but the number of scholars who are sufficiently familiar with the languages in which such chronicles are recorded is amazingly small, and smaller still is the number of such who are interested in the teaching and worship of that Church. Consequently, Occidentals are sadly ignorant of Ethiopic Church history, and still more so of her teaching and worship.