1. I. W. White, “Point control: approximations of parabolic problems and pseudo-parabolic problems,” Appl. Anal.,12, 251–263 (1981).
2. T. W. Ting, “Parabolic and pseudo-parabolic partial equations,” J. Math. Soc. Jpn.,21, No. 3, 441–453 (1969).
3. S. I. Lyashko, “Approximate solution of pseudoparabolic equations,” Zh. Vychisl. Matem. i Mat. Fiziki,30, No. 12, 1906–1911 (1991).
4. S. I. Lyashko and S. E. Red’ko, “Approximate solution of the problem of dynamics of a viscous stratified liquid,” Zh. Vychisl. Matem. Mat. Fiziki,27, No. 5, 720–729 (1987).
5. Yu. M. Berezanskii, Expansion of Selfadjoint Operators in Eigenfunctions [in Russian], Naukova Dumka, Kiev (1965).