@article{JRAM_1977__295_151926,
     author = {Jan van Leeuwen},
     title = {An extension of {Hansen's} theorem for star chains.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {202--207},
     publisher = {mathdoc},
     volume = {295},
     year = {1977},
     zbl = {0355.10040},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1977__295_151926/}
}