Maleev obtained Green's function for the 1D DKP model in 1960. He described, in principle, the general procedure to obtain Green's function for a cubic 3D DKP model. However, the problem is that only the 1D result was somehow analytical (while not taking into account the hard reproducibility of the very lengthy and tedious calculations), and in higher dimensions, it is simply easier to model the systems numerically (just as Berezin did in 1986 with the calculation of effective electron masses for 1D, 2D and 3D DKP models 127 ). Fortunately, Kasamanyan obtained the final result for the 1D DKP Green's function in 1972. However, to use it in any other context, one needs to repeat Maleev's procedure. Unfortunately, it turned out to be not really generalizable except for the case of the Shah function (i.e., the sum of equally-spaced Dirac deltas). Kasamanyan's result is as follows: