@article{ELMA_1971__26_141000,
     author = {Peter Bundschuh},
     title = {Zwei {Resultate} \"uber {Trigonalzahlen.}},
     journal = {Elemente der Mathematik},
     pages = {12--14},
     publisher = {mathdoc},
     volume = {26},
     year = {1971},
     zbl = {0206.33701},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1971__26_141000/}
}