@article{CRMATH_2007__345_7_363_0,
     author = {Bertrand, Gilles},
     title = {On critical kernels},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {363--367},
     publisher = {Elsevier},
     volume = {345},
     number = {7},
     year = {2007},
     doi = {10.1016/j.crma.2007.09.001},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/j.crma.2007.09.001/}
}