Slavka Draganova, “Koliçestven Analiz na Ovtsevidstvoto v Bılgarskite Zemi Pod Osmanska Vlast ot Sredata na XIX vek do Osvobojdeniyeto (A Quantitative Analyses of Sheep-Breeding in Bulgarian Lands under Ottoman Domination from the Middle of the XIX C. to the Liberation), Bulgar İlimler Akademisi Yay