@article{SF_1993__47_2_135288,
     author = {N. Levan},
     title = {A non-spectral representation of shift semigroups.},
     journal = {Semigroup forum},
     pages = {381--388},
     publisher = {mathdoc},
     volume = {47},
     number = {2},
     year = {1993},
     zbl = {0801.47027},
     url = {http://geodesic.mathdoc.fr/item/SF_1993__47_2_135288/}
}