@article{CRMATH_2018__356_5_482_0,
     author = {Bramati, Roberto and Casarino, Valentina and Ciatti, Paolo},
     title = {On the norms of quaternionic harmonic projection operators},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {482--488},
     publisher = {Elsevier},
     volume = {356},
     number = {5},
     year = {2018},
     doi = {10.1016/j.crma.2018.03.011},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/j.crma.2018.03.011/}
}