K. A. Breckner, „A Comparative Study of "Godmanhood" (bogochelovechestvo) in Russian Philosophy. The Eighth Day in V. Solovëv, S. Bulgakov, N. Berdiaev, and S. Frank“, Rocz. Fil. Ign., Bd. 19, Nr. 1, S. 116-152, Juni 2013.