Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
paperback [ˈpeɪpəbæk] n кни́га в мя́гкой обло́жке
adj
paperback edition изда́ние в мя́гкой обло́жке
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.