Ambigei และ Rasiah Kamala. (1998) The efficiency of educational management and school effectiveness in secondary education in Sri Lanka. Mahidol University,:ม.ป.ท.Ambigei และ Rasiah Kamala. 1998. The efficiency of educational management and school effectiveness in secondary education in Sri Lanka. ม.ป.ท.:Mahidol University,;Ambigei และ Rasiah Kamala. The efficiency of educational management and school effectiveness in secondary education in Sri Lanka. ม.ป.ท.:Mahidol University, 1998. Print.