@article{MAN_1978__232_163081,
     author = {A. Rigas},
     title = {Some {Bundles} of {Non-Negative} {Curvature.}},
     journal = {Mathematische Annalen},
     pages = {187--194},
     publisher = {mathdoc},
     volume = {232},
     year = {1978},
     zbl = {0354.53039},
     url = {http://geodesic.mathdoc.fr/item/MAN_1978__232_163081/}
}