DE LIS, JOSÉ SABINA, y SERGIO SEGURA DE LEÓN. «The limit as p → 1 of the higher eigenvalues of the p-laplacian operator -δp». Indiana University Mathematics Journal, vol. 70, n.º 4, 2021, pp. 1395-1439, https://doi.org/10.1512/IUMJ.2021.70.8563.