@article{MM2_1978__24_154534,
     author = {Stefan Hildebrandt},
     title = {Mathematical {Aspects} of {'T} {Hooft's} {Eigenvalue} {Problem} in {Two-Dimensional} {Quantum} {Chromodynamics.} {Part} {I.} {A} variational approach, and nodal properties of the eigenfunctions.},
     journal = {Manuscripta mathematica},
     pages = {45--80},
     publisher = {mathdoc},
     volume = {24},
     year = {1978},
     zbl = {0375.45004},
     url = {http://geodesic.mathdoc.fr/item/MM2_1978__24_154534/}
}