@article{NUMA_1968__11_131807,
     author = {S. HELLER},
     title = {On the {Uniform} {Positivity} of a {Certain} {Finite} {Difference} {Matrix.}},
     journal = {Numerische Mathematik},
     pages = {46--52},
     year = {1968},
     volume = {11},
     zbl = {0155.47001},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1968__11_131807/}
}