Chobanov, Georgi; Chobanov, Ivan Gibbs-Appell’s non-holonomic equations as projections of Euler’s dynamical axioms on appropriate axes. (English) Zbl 0713.70010 God. Sofij. Univ. “Kliment Okhridski”, Fak. Mat. Mekh. 79(1985), No. 2, 61-105 (1989). MSC: 70F25 70E15 70A05 PDFBibTeX XMLCite \textit{G. Chobanov} and \textit{I. Chobanov}, God. Sofiĭ. Univ., Fak. Mat. Mekh. 79, No. 2, 61--105 (1989; Zbl 0713.70010)
Diamandiev, Vasil On the invariants in Harlamov’s equations for the motion of a heavy rigid body having a fixed point. (Bulgarian. Russian, English summaries) Zbl 0712.70014 God. Sofij. Univ. “Kliment Okhridski”, Fak. Mat. Mekh. 79(1985), No. 2, 169-178 (1989). MSC: 70E05 PDFBibTeX XMLCite \textit{V. Diamandiev}, God. Sofiĭ. Univ., Fak. Mat. Mekh. 79, No. 2, 169--178 (1989; Zbl 0712.70014)