journal "Morphologia", E. office of 2017. Review Boichuk NV et al., authors; Ulumbekov EG, Chelyshev YuA, editors. Gistologiya. Embriologiya. Tsitologiya [Histology. Embryology. Cytology]: textbook. Ed. 4th, revised and additional. Moscow: GEOTAR-Media; 2016. 927 p. Russian. Морфологія / Morphologia / Morfologìâ. 11, 1 (Mar. 2017), 87. DOI:https://doi.org/10.26641/1997-9665.2017.1.87.