@article{10_21136_CPM_1980_108245,
     author = {Novotn\'a, Jarmila},
     title = {Discrete analogues of {Wirtinger's} inequality for a two-dimensional array},
     journal = {\v{C}asopis pro p\v{e}stov\'an{\'\i} matematiky},
     pages = {354--362},
     publisher = {mathdoc},
     volume = {105},
     number = {4},
     year = {1980},
     doi = {10.21136/CPM.1980.108245},
     mrnumber = {597912},
     zbl = {0454.26007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CPM.1980.108245/}
}