Martínez Reyes, M., Soberanes Martín, A. and Sánchez Soto, J. M. (2018) “The importance of variation in the concept of function: a case of exploration through the use of technology”, Programación Matemática y Software, 10(2), pp. 63–70. doi: 10.30973/progmat/2018.10.2/7.