Bulgarians by Birth : the comitopuls, Emperor Samuel and their successors according to historical sources and the historiographic tradition / Vasilka Tăpkova-Zaimova ; Translated by Pavel Murdzhev. - Leiden : Koninklijke Brill Nv, 2017. - 338 s. ; 24 cm. - (East Central and Eastern Europe in the middle ages, 450-1450 ; vol. 47). - ISBN 978-90-04-35238-4.