1. Intermediate spaces and interpolation;Calderón, A.-P.;Studia Math. (Ser. Specjalna) Zeszyt,1963
2. 2. G. H. Hardy, J. E. Littlewood and G. Pólya, Inequalities, University Press, Cambridge, 1934.
3. 3. S. G. Kreĭn and E. M. Semenov, On a space scale, Soviet Math. Dokl. 2 (1961), 706-710.
4. Sur une classe d’espaces d’interpolation;Lions, J.-L.;Inst. Hautes \'{E}tudes Sci. Publ. Math.,1964
5. Some new functional spaces;Lorentz, G. G.;Ann. of Math. (2),1950