@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 },

issn = { 0272-8893 },

pages = { 61-80 },

}