Petkov, K. (2008). The voices of medieval Bulgaria, seventh-fifteenth century: The records of a bygone culture. Brill.
芝加哥风格引文Petkov, Kiril. The Voices of Medieval Bulgaria, Seventh-fifteenth Century: The Records of a Bygone Culture. Leiden ; Boston [Mass.]: Brill, 2008.
MLA引文Petkov, Kiril. The Voices of Medieval Bulgaria, Seventh-fifteenth Century: The Records of a Bygone Culture. Brill, 2008.
警告：这些引文格式不一定是100％准确.