10.2345/0899-8205-43.1.73
10.2345/0899-8205-43.5.408
10.2345/0899-8205-47.4.343
10.2345/0899-8205-47.s1.37
10.2345/0899-8205-47.s1.42
10.2345/0899-8205(2008)42[76:EASOEO]2.0.CO;2