@article{ZNSL_2003_296_a2,
     author = {L. Yu. Kolotilina},
     title = {On the extreme eigenvalues of block $2\times2$ {Hermitian} matrices},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {27--38},
     publisher = {mathdoc},
     volume = {296},
     year = {2003},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2003_296_a2/}
}