1. P. Enflo, J. Lindenstrauss, and G. Pisier, ?On the three space problem,? Math. Scand.,36, No. 2, 199?210 (1975).
2. S. A. Rakov, ?Ultraproducts and the three space problem,? Funkts. Anal. Prilozhen.,11, No. 3, 88?89 (1977).
3. B. V. Godun and S. A. Rakov, ?The Banach-Saks property and the three space problem,? Mat. Zametki,31, No. 1, 61?74 (1982).
4. M. I. Ostrovskii, ?The Banach-Saks property, injectivity, and the openings of the subspaces of a Banach space,? Teor. Funktsii Funkts. Anal. Prilozhen.,44, 69?78 (1985).
5. B. Beauzamy and J. T. Lapresté, Modeles Etales des Espaces de Banach, Hermann, Paris (1983).