@article{10_1017_S0017089500032419,
     author = {Duggal, B. P.},
     title = {On the spectrum of n-tuples of p-hyponormal operators},
     journal = {Glasgow mathematical journal},
     pages = {123--131},
     year = {1998},
     volume = {40},
     number = {1},
     doi = {10.1017/S0017089500032419},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500032419/}
}