1. Circumventing visual limitations in teaching the geometry of shapes;Triadafillidis;Educ. Stud. Math.,1995
2. Geometry: Educational implications for children with visual impairment;Klingenberg;Philos. Math. Educ. J.,2007
3. Foundation of Education: Volume II, Instructional Strategies for Teaching Children and Youths with Visual Impairments;Koenig,2000
4. Tactual shape perception in relation to the understanding of geometrical concepts by blind students;Argyropoulos;Br. J. Vis. Impair.,2002
5. Learning and Teaching Early Math: The Learning Trajectories Approach;Clements,2014