Department of Information, Systems And Quantitative, Sciences Nanzan University 18, Yamazato-Cho, Showa-Ku, Nagoya 466, Japan
Bibliografia
[1] U. Avraham, K. Devlin and S. Shelah, The consistency with CH of some consequences of Martin's Axiom plus $2^α_0 > α_1$, Israel J. Math. 31 (1978), 19-33.
[2] S. Shelah, Proper Forcing, Lecture Notes in Math. 940, Springer, 1982.