@article{10_2298_PIM0900123S,
     author = {Tariq Shah and Ehsan Ullah},
     title = {Factorization properties of subrings in trigonometric polynomial rings},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {123 },
     publisher = {mathdoc},
     volume = {_N_S_86},
     number = {100},
     year = {2009},
     doi = {10.2298/PIM0900123S},
     zbl = {1221.13001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.2298/PIM0900123S/}
}