Beverley (2011), p. 48. Beverley, J.A. (2011). "Ashura". In Gordon Melton, J. (ed.). Religious Celebrations: An Encyclopedia of Holidays, Festivals, Solemn Observances, and Spiritual Commemorations. ABC-CLIO. pp. 47–49. ISBN9781598842050.
Seidelmann (1992), p. 577: "For convenience, it is common to speak of a lunar year of twelve synodic months, or 354.36707 days. Seidelmann, P. Kenneth, ed. (1992). Explanatory Supplement to the Astronomical Almanac.