Probably the only text in English on Hauer's Klangreihen and dodecaphony (and those of his followers Steinbauer, Sengstschmid, Neumann). The subject is treated in Italian only and exclusively in Alberto Colla's Manuale di Armonia Moderna e Contemporanea (published by Carisch)
https://www.amazon.co.uk/Serial-Composition-Tonality-Dominik-Sedivy/dp/3902796030