1. Buryakov N.P., Buryakova M.A., Rational feeding of dairy cattle (M. RSAU-MAA, 2015) 314.
2. Garajyan A.M., Marmaryan Yu.G., Methods of experimental work in animal husbandry (Yer., 2004) 215.
3. Giloyan G. A., Azizyan A.V., Kasumyan N.A., Growth and development of animals. Handbook (Yer., 2016) 100.
4. Giloyan G.A., Kasumyan N.A., Genealogical analysis of imported heifers of Fleckvieh and Holstein breeds in the production association “Agroservice” Materials of the conference of the International Academy of Veterinary Medical Sciences of the Republic of Armenia 2010 (Yerevan, 2011) 29-30.