Graded go problemsfor beginners 4. Yano Yoshinori, 9 dan - Kiseido 1997 - En anglais - 197 p. Chap. 1 : Advanced problems, level 1 Chap. 2 : Advanced problems, level 2 Chap. 3 : Advanced problems, level 3, life and death problems Chap. 4 : Advanced problems, level 4, life and death problems