Kopas I.M., Spichak S.V., Stognii V.I. Group classification of one class of (2+1)-dimensional linear pricing equations for Asian options, Bukovinian Mathematical Journal, 2022, V. 10, N 2, 240-248 (in Ukrainian).
Gorbunova O., Kopas I., Spichak S.V., Stognii V. Symmetric properties and exact solutions of the (2+1)-dimensional linear Asian option pricing equation, Modern problems of mechanics and mathematics, Proceedings of Institute of Applied Problems of Mechanics and Mathematics named Ya.S. Pidstryhach, NAS of Ukraine, Lviv, 2018, V. 3, 165-166 (in Ukrainian).
Rassoha I.V., Serov M.I., Spichak S.V., Stognii V.I. Group classification of nonlinear equations of Kolmogorov type, Scientific Bulletin of the National Technical University of Ukraine "KPI", 2013, N 4, 88-93 (in Ukrainian).
Spichak S.V. Preliminary classification of realizations of two-dimensional Lie algebras of vector fields on a circle, in Proceedings of 6th Workshop "Group Analysis of Differential Equations and Integrable Systems" (June 17-21, 2012, Protaras, Cyprus), University of Cyprus, Nicosia, 2013, 212-218.
Spichak S.V., Stognii V.I., Kopas I.M. Symmetric analysis and exact solutions of the linear equation Kolmogorov, Scientific Bulletin of the National Technical University of Ukraine "KPI", 2011, N 4, 93-97 (in Ukrainian).
Spichak S.V., On algebraic classification of Hermitian quasi-exactly solvable matrix Schrodinger operators on line, in Proceedings of 5th Workshop "Group Analysis of Differential Equations and Integrable Systems" (June 6-10, 2010, Protaras, Cyprus), University of Cyprus, Nicosia, 2011, 184-199.
Lahno V.I., Spichak S.V. Group classification of quasi-linear elliptic type equations. II. Invariance under solvable Lie algebras, Ukrainian Mathematical Journal, 2011, V. 63, N 2, 200-215 (in Ukrainian).
Nikitin A.G., Spichak S.V., Vedula Yu. S., Naumovets A.G. Symmetries and modelling functions for diffusion processes, J. Phys. D: Appl. Phys., 2009, V. 42, 055301, 12 pp.
Lahno V.I., Spichak S.V., Quasi-linear elliptic type equations invariant under five-dimensional solvable Lie algebras, in Proceedings of 4th Workshop "Group Analysis of Differential Equations and Integrable Systems" (October 26-30, 2008, Protaras, Cyprus), University of Cyprus, Nicosia, 2009, 121-134.
Lahno V.I., Spichak S.V. Group analysis of quasilinear equations of elliptic type with respect to solvable Lie algebras, Proceedings of International Conference "Some actual problems of modern mathematics and mathematical education" (May, 2008, Saint Petersburg, Russia), Russian State Pedagogical University, Saint Petersburg, 2008, 75-79 (in Russian).
Lahno V.I., Spichak S.V. Group classification of quasi-linear elliptic type equations. I. Invariance under Lie algebras with nontrivial Levi decomposition, Ukrainian Mathematical Journal, 2007, V. 59, N 11, 1532-1545 (in Ukrainian).
Spichak S.V. Group classification of quasi-linear elliptic type equations, in Proceedings of International Conference ``Differencial Equations and Related Topics'' (21-26 May, 2007, Moscow): Book of Abstracts. - Moscow: Moscow University Press, 2007. 379 P.
Spichak S.V. Preliminary group classification of general two-dimensional quasi-linear elliptic type equations, Symmetry and integrability of equations of mathematical physics, Inst. Mathematics of National Akad. Science of Ukraine, Kiev, 2006, V. 3, N 2, 284-292. (pdf)
Lahno V.I., Spichak S.V. Preliminary group classification of quasi-linear elliptic type equations, in Proceedings of International Conference ``Modern methods in physical-mathematical sciences'' (9-14 October, 2006, Orel), Editor A.G. Meshkov, Orel State university, 2006, V.1, 79-83 (in Russian).
Spichak S.V., Invariance of Maxwell's Equations under Nonlinear Representations of Poincar\'e Algebra, in Proceedings of Fifth International Conference ``Symmetry in Nonlinear Mathematical Physics'' (23-29 June, 2003, Kyiv), Editors A.G. Nikitin, V.M. Boyko, R.O. Popovych and I.A. Yehorchenko, Proceedings of Institute of Mathematics, Kyiv, 2004, V.50, Part 2, 961-964 [pdf].
Lahno V.I., Spichak S.V., Stognii V.I. Symmetry analysis of evolution type equations, Kyiv, Institute of Mathematics of NAS of Ukraine, 2002, 360 p. (in Ukrainian) (you can download here ps and pdf).
Spichak S.V. On multi-parameter families of Hermitian exactly solvable matrix Schrödinger models, Symmetry in nonlinear mathematical physics, Part 1, 2, Proceedings of Inst. Mathematics of National Akad. Science of Ukraine (Kiev, 2001), 2002, V. 43, 688-690 (pdf).
Abramenko A.O., Spichak S.V. On new classes of Hermitian exactly solvable matrix Schrödinger operators, Mat. Stud., 2001, V. 15, N 1, 44-56 (in Ukrainian).
Abramenko A.O., Spichak S.V. Multiparameter families of Hermitian exactly solvable matrix Schrödinger models, Group and analytic methods in mathematical physics, Proceedings of Inst. Mathematics of National Akad. Science of Ukraine, Kiev, 2001, V. 36, 12-24 (in Ukrainian). (pdf)
Spichak S.V., Stognii V.I. One-dimensional Fokker-Planck equation invariant under four- and six-parametrical group, Symmetry in nonlinear mathematical physics, Part 1, 2, Proceedings of the Conference of Inst. Mathematics of National Akad. Science of Ukraine, Kiev (1999), 2000, V. 30, Part 1, 204-209 (pdf).
Spichak S.V., Stognii V.I. Symmetric classification of the one-dimensional Fokker-Planck-Kolmogorov equation with arbitrary drift and diffusion coefficients, Nonlinear oscillations, 1999, V. 2, N 3, 401-413 (in Russian).
Spichak S.V. Quasi-exactly solvable 2x2 matrix Schrödinger models, Proceedings of the XXX Symposium on Mathematical Physics (Torun, 1998). Rep. Math. Phys., 1999, V. 44, no. 1-2, 215-220.
Spichak S.V., Stognii V.I. Symmetry classification and exact solutions of the one-dimensional Fokker-Planck equation with arbitrary coefficients of drift and diffusion, J. Phys. A, 1999, V. 32, N 47, 8341-8353.
Spichak S.V., Zhdanov R.Z. On algebraic classification of Hermitian quasi-exactly solvable matrix Schrödinger operators on line, J. Phys. A, 1999, V. 32, N 20, 3815-3831 (see math-ph/9812001).
Spichak S.V., Stognii V.I. Symmetry classification and exact solutions of the Kramers equation, J. Math. Phys., 1998, V. 39, N 6, 3505-3510.
Spichak S.V. Invariance of the Maxwell equations with respect to nonlinear representations of the Poincaré algebra, Symmetry and analytic methods in mathematical physics, Inst. Mathematics of National Akad. Science of Ukraine, Kiev, 1998, V. 19, 221-225 (in Russian). (pdf)
Spichak S.V., Stogny V.I. Symmetry analysis of the Kramers equation, Rep. Math. Phys., 1997, V. 40, N 1, 125-130.
Spichak S.V., Stognii V.I. Conditional symmetry and exact solutions of the Kramers equation, Symmetry in nonlinear mathematical physics, Vol. 1, 2 (Kiev), 1997, 450-454 (pdf).
Spichak S.V. On the Poincaré-invariant second-order partial equations for a spinor field, J. Nonlinear Math. Phys., 1996, V. 3, no. 1-2, 156-159 (pdf).
Shtelen W.M., Spichak S.V. Lie and Q-conditional symmetry and exact solutions of local Wilson renormalization group equation, Symmetry analysis of equations of mathematical physics, Acad. Sci. Ukraine, Inst. Math., Kiev, 1992, 50-54.
Fushchich W.I., Shtelen W.M. and Spichak S.V. On the connection between solutions of Dirac and Maxwell equations, dual Poincaré invariance and superalgebras of invariance and solutions of nonlinear Dirac equations, J. Phys. A, 1991, V. 24, N 8, 1683-1698 (pdf).
Fushchich V.I., Shtelen V.M. and Spichak S.V. On a connection between solutions of Dirac and Maxwell equations. Supersymmetry of the Dirac equation, Reports of Akad. Science of Ukrain SSR, Ser. A , 1990, V. 87, N 3, 36-40 (in Russian) (pdf).
Spichak S.V., Vector representation of the Poincaré algebra and exact solution of the Dirac equation, Algebra-theoretic analysis of equations in mathematical physics (in Russian), Akad. of Science of Ukraine SSR, Institute of Mathematics, Kiev, 1990, 70-73.
Spichak S.V. A new second-order conformally invariant equation for a spinor field, Symmetry and solutions of equations of mathematical physics, Akad. of Science of Ukrain. SSR, Inst. Mathematics, Kiev, 1989, 79-81 (in Russian).
Shtelen V.M., Spichak S.V. On the invariance of the Dirac equation with respect to different representations of the Poincaré algebra, Symmetry and solutions of equations of mathematical physics, Akad. of Science of Ukrain. SSR, Inst. Mathematics, Kiev, 1989, 114-118 (in Russian).
