@article{ASNSP_1972_3_26_4_839_0,
     author = {Lorenzi, A.},
     title = {On elliptic equations with piecewise constant coefficients. {II}},
     journal = {Annali della Scuola Normale Superiore di Pisa - Scienze Fisiche e Matematiche},
     pages = {839--870},
     publisher = {Scuola normale superiore},
     volume = {Ser. 3, 26},
     number = {4},
     year = {1972},
     mrnumber = {382836},
     zbl = {0252.35019},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1972_3_26_4_839_0/}
}