1. H. Triebel, Interpolation Theory, Function Spaces, Differential Operators (North-Holland, Amsterdam, 1978; Mir, Moscow, 1980).
2. J. Bergh and J. Löfström, Interpolation Spaces: An Introduction (Springer, Berlin, 1976; Mir, Moscow, 1980).
3. Pure Appl. Math;J Dieudonné,1960
4. Pure Appl. Math;J Pöschel,1987
5. J. Bergh, “A nonlinear complex interpolation result,” in Lecture Notes in Math., Vol. 1070: Interpolation Spaces and Applied Topics in Analysis (Springer, Berlin, 1984), pp. 45–47.