From the introduction: "In this paper I give a brief description of a reanalysis of the tone system of Diuxi Mixtec previously analyzed by Eunice Pike and Joy Oram (1976). Their analysis is heavily influenced by their conception of probably phonetic manifestations of tone, whereas my analysis is more influenced by morphophonemic considerations. Giving more attention to morphophonemic considerations in determining tone phonemes makes possible a simpler account of the morphophonemics of tone. This account, however, is not at the expense of phonetic simplicity but is compatible with a phonetically reasonable and relatively simple account of allphonic processes."
Daly, John P.
"Notes on Diuxi Mixtec tone,"
Work Papers of the Summer Institute of Linguistics, University of North Dakota Session: Vol. 22, Article 3.
Available at: https://commons.und.edu/sil-work-papers/vol22/iss1/3