@article{PORMA_1989__46_1_115650,
     author = {Haukkanen, Pentti},
     title = {Comparison of regular convolutions},
     journal = {Portugaliae mathematica},
     pages = {59--69},
     publisher = {mathdoc},
     volume = {46},
     number = {1},
     year = {1989},
     mrnumber = {0996402},
     zbl = {0668.10012},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1989__46_1_115650/}
}