[1] Chiang Mai Univ & Watket, Payap Univ, Fac Nursing, McCormick Fac Nursing, Chiang Mai, Thailand
[2] Chiang Mai Univ, Fac Nursing, 110 Intawaroros Rd, Chiang Mai, Thailand
[3] Univ Calif San Francisco, Sch Nursing, Dept Physiol Nursing, 2 Koret Way, San Francisco, CA 94143 USA