@article{10_4153_CMB_2011_041_7,
     author = {Mortad, Mohammed Hichem},
     title = {On the {Adjoint} and the {Closure} of the {Sum} of {Two} {Unbounded} {Operators}},
     journal = {Canadian mathematical bulletin},
     pages = {498--505},
     year = {2011},
     volume = {54},
     number = {3},
     doi = {10.4153/CMB-2011-041-7},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-2011-041-7/}
}