The Miltary Activity of the Order of the Sword Brethren (1202-1236) - Mugurēvičs, Ēvalds (. The @North-Eastern frontiers of Medieval Europe. - Farnham [u.a.] : Ashgate, 2014. - XLIX, 389 S.. - Ill., graph. Darst., Kt.. - ISBN 978-1-4094-3680-5, 2014)