1. I. M. Gelfand and I. S. Zakharevich, Spectral theory of a pencil of third-order skew-symmetric differential operators on s
1, Functional Analysis and its Applications 23 (1989), no. 2, 85–93.
2. I. M. Gelfand and I. S. Zakharevich —, Webs, Veronese curves, and bi-Hamiltonian systems, Journal of Functional Analysis 99 (1991), no. 1, 150–178.
3. Israel M. Gelfand and Ilya Zakharevich, The spectral theory for a pencil of skew-symmetrical differential operators of third order, preprint MSRI-06627-91, MSRI, Berkeley, CA, 94720, 1991.
4. Alexander Goncharov, private communication, 1990.
5. Kunihiko Kodaira, Complex manifolds and deformation of complex structures, Grundlehren der mathematischen Wissenschaften, vol. 283, Springer-Verlag, New York, 1986.