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\bibitem{Graf2011} Graf, S., Kinshuk, Chang, M., Dron, J., i Wen, D., Kumar, V., Tan, Q., Yang, G., Lin, O., \& Chen, N.-S. (2011). Adaptivity and Personalization in Ubiquitous Learning Environments -- Learning Styles based Approach. \textit{Revista Magisterio Journal}, \textit{52}, 30--39.

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