J. J. . Nieto y R. . Rodríguez López, «Applications of Contractive-like Mapping Principles to Fuzzy Equations», Rev. mat. complut., vol. 19, n.º 2, pp. 361–383, jul. 2006, doi: https://doi.org/10.5209/rev_REMA.2006.v19.n2.16599