@article{ELMA_1955__10_140626,
     author = {K. Strubecker},
     title = {\"Uber die {H\"ullkurven} von {Kepler-Bahnen} fester {Energie,} welche eine feste {Kepler-Bahn} ber\"uhren.},
     journal = {Elemente der Mathematik},
     pages = {81--86},
     publisher = {mathdoc},
     volume = {10},
     year = {1955},
     zbl = {0065.13606},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1955__10_140626/}
}