@article{NUMA_1993__65_4_133748,
     author = {Mitsuhiro T. Nakao and N. Yamamoto},
     title = {Numerical verifications of solutions for elliptic equations in nonconvex polygonal domains.},
     journal = {Numerische Mathematik},
     pages = {503--522},
     publisher = {mathdoc},
     volume = {65},
     number = {4},
     year = {1993},
     zbl = {0797.65081},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1993__65_4_133748/}
}