The master thesis of Horst Bernhard Loeschmann, "The Byzantine Communion Chant for Easter in 14th-Century Manuscripts" (The University of British Columbia, 1982).
https://circle.ubc.ca/bitstream/handle/2429/23064/UBC_1982_A8%20L64.pdf
https://circle.ubc.ca/bitstream/handle/2429/23064/UBC_1982_A8%20L64.pdf