1. On imaginary quadratic number fields with 2-class group of rank 4 and infinite 2-class field tower;Benjamin;Pacific J. Math.,2001
2. On a question of Martinet concerning the 2-class field tower of imaginary quadratic number fields;Benjamin;Ann. Sci. Math. Québec,2002
3. Algebraic Number Theory;Cassels,1986
4. On class field towers;Golod;Izv. Akad. Nauk SSSR,1964