@article {Thomson1987, title = {The Problem of the Reception of the Works of John {IV} Ieiunator of Constantinople among the Slavs: Nicon of the Black Mount and Cirycus of Novgorod}, journal = {Palaeobulgarica / Старобългаристика}, volume = {11}, year = {1987}, pages = {23{\textendash}45}, author = {Francis J Thomson} }