@article{RSMUP_2003__110__269_0,
     author = {Diagana, Toka},
     title = {Algebraic sum of unbounded normal operators and the square root problem of {Kato}},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {269--275},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {110},
     year = {2003},
     mrnumber = {2033011},
     zbl = {1121.47015},
     language = {en},
     url = {http://www.numdam.org/item/RSMUP_2003__110__269_0/}
}