@article{NUMA_1977__29_132509,
     author = {A. Spence},
     title = {Error {Bounds} and {Estimates} for {Eigenvalues} of {Integral} {Equations.}},
     journal = {Numerische Mathematik},
     pages = {133--148},
     publisher = {mathdoc},
     volume = {29},
     year = {1977},
     zbl = {0358.65109},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1977__29_132509/}
}