@Article{ MOLINA_Ambrose-:61-80,
author = { MARTA MOLINA and Rebecca Ambrose- } ,
title = { FROM AN OPERATIONAL TO A RELATIONAL CONCEPTION OF THE EQUAL SIGN. THIRDS GRADERS¿ DEVELOPING ALGEBRAIC THINKING. },
journal = { Focus on learning problems in mathematics },
year = { 2008 },
volume = { 30 },
pages = { 61-80 },
}