↑Roman Jakobson, Comparative Slavic Studies. The Cyrillo-Methodian Tradition, Walter de Gruyter, 1985 : « The name of the first bishop of Cracow, Prohor (Prochor), and also probably the name of his successor, Prokulf (Proklus), belong to the Byzantine world. »
Bibliographie
Jerzy Kłoczowski, Histoire religieuse de la Pologne, Le Centurion, 1987, p. 27.