isoglosses
Constantine Leo Borissoff, A. C. Shaposhnikov. Russian-sanskrit etymological sketches
Trudy IRY RAS. 2018. № 4 (18), Pages. 33 - 73
Tatiana V. Popova. East Slavic linguistic and geographical problems *
Trudy IRY RAS. 2017. № 2 (12), Pages. 240 - 262