Golovashkin A.I. , Mitsen K.V. , Ivanenko O.M. , Pavlovskii A.I. , Kolokolchikov N.P. , Platonov V.V. , Tatsenko O.M. , Deryugin Y.N. Destruction of superconductivity in YBa_2Cu_3O_7 ceramics by ultrahigh magnetic field. Intern. conf. on Superconductivity. Bangalore, India, 10-14 Jan. 1990 , с. P.302