@article{CMUC_2002_43_2_a14,
     author = {Tian, Yongge and Styan, George P. H.},
     title = {A new rank formula for idempotent matrices with applications},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {379--384},
     year = {2002},
     volume = {43},
     number = {2},
     mrnumber = {1922135},
     zbl = {1090.15001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_2002_43_2_a14/}
}