1. Yu.A. Kravtsov: Izv. VUZ Radiofiz. 8,659 (1965) [English transl.: Sov. Radiophys. 8,467 (1965)]
2. Yu.A. Kravtsov: Sov. Phys. - Acoust 14, 1 (1968)
3. Yu.A. Kravtsov: In Analiticheskie Methody v Teorii Difraktsii Rasprostraneniya Voln (analytic methods in diffraction and wave propagation theory) (Nauchnyi Soviet poAkustike, Akad, Nauk SSSR, Moscow 1970) pp. 258–362
4. G.B. Airy: Trans. Cambridge Philos. Soc. 6, 379 (1838)
5. R.N. Bûchai, J.B. Keller: Commun. Pure Appl. Math. 13, 85 (1960)