Inskeep، J. E. (1960). A comparison of serveral methods of estimating readiability of elementary school reading material (رسالة دكتوراه غير منشورة). University of Minnesota، مينيسوتا. مسترجع من http://search.mandumah.com/Record/544898
Inskeep، James Edward. "A Comparison of Serveral Methods of Estimating Readiability of Elementary School Reading Material" رسالة دكتوراه. University of Minnesota، مينيسوتا، 1960. مسترجع من http://search.mandumah.com/Record/544898