Whitney-type theorems on extension of functions on Carnot groups. Vodop'yanov, S.K.; Pupyshev, I.M. — 2006 Sibirskij Matematicheskij Zhurnal
Traces of Sobolev functions on the Ahlfors sets of Carnot groups. Vodop'yanov, S.K.; Pupyshev, I.M. — 2007 Sibirskij Matematicheskij Zhurnal