@article{ASNSP_1997_4_25_1-2_131_0,
     author = {Boffi, Daniele and Brezzi, Franco and Gastaldi, Lucia},
     title = {On the convergence of eigenvalues for mixed formulations},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {131--154},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 25},
     number = {1-2},
     year = {1997},
     mrnumber = {1655512},
     zbl = {1003.65052},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1997_4_25_1-2_131_0/}
}