Gamkrelidze, T. V. Alphabetic Writing and the Old Georgian Script (Tseris anbanuri sistema da dzveli kartuli damtserloba), 1990. In Georgian and Russian.
Genko, A. N. The Abaza Language: Grammatical Sketch of the Tapanta Dialect (Abazinskii yazyk Grammaticheskii ocherk narechiya tapanta). First edition, 1955. In Russian.