Фаддеевна Ковязина Надежда. “Invariant Entries and Gospel Lections in the Slavic Lectionary Menology of the 11–16th Cc. (September)”. Slavistica Vilnensis, Vol. 49, no. 2, Dec. 2000, pp. 51–60, doi:10.15388/SV.2000.23119.