Paper  bibtex   

@book{dobrev_old_1995,
	address = {Sofia},
	title = {Old {Bulgar} {Language} - {Vocabulary} and {Grammar} ({Ezikyt} na {Asparukhovite} i {Kuberovi} bylgari, {Rechnik} i {Gramatika})},
	url = {http://groznijat.tripod.com/b_lang/},
	urldate = {2019-09-21},
	author = {Dobrev, Peter},
	year = {1995}
}