@inbook{ GUTIERREZ_Rico-Romero_CASTRO_Castro-Martinez:179-205,

author = { JOSE GUTIERREZ PEREZ and Luis Rico-Romero and ENRIQUE CASTRO MARTINEZ and Encarnacion Castro-Martinez } ,

title = { ON THE CLASSIFICATION OF TWO-STEPS ADDITIVE PROBLEMS },

booktitle = { DIDACTICS OF MATHEMATICS-TECHNOLOGY IN EDUCATION },

isbn = { 960-312-063-4 },

publisher = { ART OF TEXT },

pages = { 179 - 205 },

year = { 1997 },

}