1. J. Appel and O. W. Diallo, “Problemes aux limites pour des equations integro-differentielles de type Barbachine,” Z. Anal. Anwendungen, 14, No.1, 95–104 (1995).
2. E. A. Barbashin, Introduction to Stability Theory [in Russian], Nauka, Moscow, (1967).
3. Yu. M. Berezanskii, Expansion in Eigenfunctions of Self-adjoint Operators [in Russian], Naukova Dumka, Kiev (1965).
4. I. S. Berezin and N. P. Zhidkov, Methods of Calculation [in Russian], Vol. 2, Nauka, Moscow (1962).
5. J. Bernoulli, “Dechordis vibrantibls,” Commentarii Academiae Scientiarum Imperialis Petropolitanae, 3, 13–28 (1728).