The authors consider the neutron diffusion in an isotropically scattering plane-parallel medium of finite thickness in which are situated a plane source at the middle and a uniformly distributed point source. The transport equation is supplemented with boundary conditions which specify on the two parallel surfaces flux of beams normally incident from outside. The unknown density distribution is conveniently written as the sum of its scattered part and nonscattered part. The integro-differential equation for the scattered density distribution is solved by the Laplace transform combined with the Wiener-Hopf technique. The article contains some misprints and excessive computations.