2Reys, R.E.& Grouws, D.A. ( 1975 ) .Division involving zero:Some revealing thoughts from interviewing children.School Science and Mathematics,75 (7):593- 605.
3Wheeler, M.M.& Feghali,I. (1983).Much ado about nothing:Preservice elementary school teachers' concept of zero.Journal for Research in Mathematics Education, 14(3) : 147-155.
4Ball,D.L. (1990). Prospective elementary and secondary teachers' understanding of division.Journal for Research in Mathematics Education,21:132-144.
5Even, R., & Tirosh, D. ( 1995 ). Subject-matter knowledge and knowledge about students as sources of teacher presentations of the subject-matter.Educational Studies in Mathematics, 29 : 1-20.
6Crespo,S.,Nicol,C. (2006).Challenging preservice teachers ' mathematical understanding : the case of division by zero.School Science and Mathematics,106 (2) : 84-97.
7Kelser,J.M.(,2OO4).Struggles with developing the concept of angle : comparing sixth- grade students ' discourse to the history of angle concept.Mathematical Thinking and Learning, 6 (3) : 285-306.
8Heath,T.L. (1968).The Thirteen Books of Euclid's Elements (Vol.1).Cambridge:The University Press.332.