The researcher analyzes the reference citations of the doctoral dissertations of the department of statistics at the University of Mosul for the period(1995-2006) which mounted to(668) reference citations. The research offered a good evaluation of the information sources used by Ph.D students. The researcher used some statistical method and the statistical program (Minitab 13). The most important conclusion is that the ratio of using foreign reference citations which mounted to(83,532%) is greater than the ratio of Arabic reference citations which mounted to (%16.467). The reason of this difference is attributed to the rarity of the Arabic information sources in statistics and the high prices of most of them.