@article{10_4064_fm_135_3_147_173,
     author = {Roman Srzednicki},
     title = {Periodic orbits indices},
     journal = {Fundamenta Mathematicae},
     pages = {147--173},
     publisher = {mathdoc},
     volume = {135},
     number = {3},
     year = {1990},
     doi = {10.4064/fm-135-3-147-173},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-135-3-147-173/}
}