A revised form of the Julian Calendar, developed by the Serbian astronomer Milutin Milanković, which mostly coincides with the Gregorian one, was finally adopted by the Greek Orthodox Patriarchate of Constantinople in 1924 as well as by the autocephalous Church of Greece.
Chrysostomos II Kioussis (1920–2010), Archbishop of Athens and All Greece of the Greek Old Calendarists in 1986–2010
Dimitri Kitsikis - The Old Calendarists and the Rise of Religious Conservatism in Greece - Etna, California,Center for Traditionalist Orthodox Studies, 1995.