1. Die Regularisierung nichtlinearer Gleichungen;Langenbach;Math. Nachr.,1962
2. Approximate methods for solving differential equations;Mikhlin,1965
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4. The method of finite differences for solving quasilinear elliptic equations with discontinuous coefficients;Sapagovas;Zh. vȳchisl. Mat. mat. Fiz.,1965
5. Investigation of difference schemes for non-linear equations by means of the variational principle;Lyashko;Izv. VUZov Ser. matem.,1967