ABBASOVA, Y. G.; KURBANOV, V. M. Convergence of the spectral decomposition of a function from the class $W_{p,m}^1 (G),\; p > 1$, in the vector eigenfunctions of a differential operator of the third order. Ukrains’kyi Matematychnyi Zhurnal, v. 69, n. 6, p. 719-733, 25 Jun. 2017.