@article{10_1007_s10587_013_0003_7,
     author = {Bhatti, Faqir M. and Das, Kinkar Ch. and Ahmed, Syed A.},
     title = {On the energy and spectral properties of the he matrix of hexagonal systems},
     journal = {Czechoslovak Mathematical Journal},
     pages = {47--63},
     publisher = {mathdoc},
     volume = {63},
     number = {1},
     year = {2013},
     doi = {10.1007/s10587-013-0003-7},
     mrnumber = {3035496},
     zbl = {1274.05224},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.1007/s10587-013-0003-7/}
}