Al Dhafi، S. (2010). Investigation Into the Students Vocabulary Learning Difficulties in Secondary School in Saudi Arabia (رسالة ماجستير غير منشورة). University of Exeter، إكستر. مسترجع من http://search.mandumah.com/Record/609789
Al Dhafi، Sara. "Investigation Into the Students Vocabulary Learning Difficulties in Secondary School in Saudi Arabia" رسالة ماجستير. University of Exeter، إكستر، 2010. مسترجع من http://search.mandumah.com/Record/609789