@Article{ MOLINA_MASON:224-242,
author = { MARTA MOLINA and JOHN H. MASON } ,
title = { JUSTIFICATIONS-ON-DEMAND AS A DEVICE TO PROMOTE SHIFTS OF ATTENTION ASSOCIATED WITH RELATIONAL THINKING IN ELEMENTARY ARITHMETIC },
journal = { CANADIAN JOURNAL OF SCIENCE, MATHEMATICS AND TECHNOLOGY EDUCATION },
year = { 2009 },
issn = { 1492-6156 },
pages = { 224-242 },
}