by L.D. Landau and E.M. Lifshitz ; translated from the Russian by J.B. Sykes and M.J. Kearsley ; pt. 1 : hardcover, pt. 1 : flexicover. -- 3rd ed., rev. and enl.. -- Pergamon Press, 1980. -- (Pergamon international library of science, technology, engineering and social studies . Course of theoretical physics; v. 5).