@article{MS2_1973__33_166331,
     author = {Peter Orlik},
     title = {Homotopy {4-Spheres} {Have} {Little} {Symmetry.}},
     journal = {Mathematica Scandinavica},
     pages = {275--278},
     publisher = {mathdoc},
     volume = {33},
     year = {1973},
     zbl = {0281.57029},
     url = {http://geodesic.mathdoc.fr/item/MS2_1973__33_166331/}
}