@article{ELMA_1974__29_141149,
     author = {O. Bottema},
     title = {A {Triangle} {Transformation.}},
     journal = {Elemente der Mathematik},
     pages = {135--138},
     publisher = {mathdoc},
     volume = {29},
     year = {1974},
     zbl = {0294.50012},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1974__29_141149/}
}