@article{10_1017_S0017089500000331,
     author = {Rotkiewicz, A.},
     title = {On the prime factors of the number 2p-1 - 1},
     journal = {Glasgow mathematical journal},
     pages = {83--86},
     year = {1968},
     volume = {9},
     number = {2},
     doi = {10.1017/S0017089500000331},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500000331/}
}