@article{MOMA_1976__81_177742,
     author = {Mary E. Gbur},
     title = {On the {Lower} {Markov} {Spectrum.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {95--108},
     publisher = {mathdoc},
     volume = {81},
     year = {1976},
     zbl = {0322.10016},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1976__81_177742/}
}