@article{RMI_1992_1992_1_a4,
     author = {Varopoulos, Nicholas Th.},
     title = {Conmutadores de semigrupo bajo diferencias.},
     journal = {Revista matem\'atica iberoamericana},
     pages = {1-43},
     publisher = {mathdoc},
     volume = {8},
     number = {1},
     year = {1992},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RMI_1992_1992_1_a4/}
}