@article{10_4064_cm_36_2_237_240,
     author = {Gerhard X. Ritter},
     title = {On fixed point free involutions of $R^1 {\texttimes} S^2$},
     journal = {Colloquium Mathematicum},
     pages = {237--240},
     publisher = {mathdoc},
     volume = {36},
     number = {2},
     year = {1976},
     doi = {10.4064/cm-36-2-237-240},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-36-2-237-240/}
}