The study of the relationship between patient status indicators and patient’s care time using multilevel analysis - Ishii, A; Ohno, Y; Kasahara, S; Hirakawa, K; Kitamura, Y; Nakamura, A; Murata, K; Inamura, K; Harauchi, H; Monden, M; Sakon, M; Fujimoto, H; Morita, T (Jpn J Med Inf, 2002)