Al-Iraqi، M. A. M. S.، و A. Allah، T. M. Z. A. E. (2012). Investigating the Difficulties in English Collocations Encountered by Sudanese Learners of English at University Levels: A Case Study of 4th Year Students at Al-Ahlia University (رسالة ماجستير غير منشورة). جامعة النيلين، الخرطوم. مسترجع من http://search.mandumah.com/Record/1339589
Al-Iraqi، Mahasin Ahmad Mohammad Salih، و Taha Mohammed Zein A. El-Wahid A. Allah. "Investigating the Difficulties in English Collocations Encountered By Sudanese Learners of English At University Levels: A Case Study of 4th Year Students At Al-Ahlia University" رسالة ماجستير. جامعة النيلين، الخرطوم، 2012. مسترجع من http://search.mandumah.com/Record/1339589