Петров, В.Рука богословия, или Наука изъяснения о пасхалии... Москва, 1787.
Russian clergyman Vasilij Petrov‘s (XVIII c.) compiled paschal tables Hand of the God‘s Word or a Discourse on Paschalian Science, to calculate movable Orthodox feasts
Volvelle at the flypaper of the book – the Moon calendar
Volvelle at the flypaper of the book – the Moon calendar
