Variable o viii warm absorber in mcg -6-30-15 - Otani, C; Kii, T; Reynolds, C S; Fabian, A C; Iwasawa, W; Hayashida, K; Inoue, H; Kunieda, Hironobu; Makino, F; Matsuoka, Masao; Tanaka, Y (Publications of the Astronomical Society of Japan, 1996)