Pojana Wongtrakool. 1995. Instructional leadership of principals and student achievement in private lower secondary schools of Thailand. Illinois:Illinois State University;
Pojana Wongtrakool. (1995) Instructional leadership of principals and student achievement in private lower secondary schools of Thailand (รายงานผลงานวิจัย). Illinois State University:Illinois.
Pojana Wongtrakool. Instructional leadership of principals and student achievement in private lower secondary schools of Thailand. Illinois:Illinois State University, 1995.
Pojana Wongtrakool. (1995) Instructional leadership of principals and student achievement in private lower secondary schools of Thailand (รายงานผลงานวิจัย). Illinois State University:Illinois.