REFERENCES
- Anderson , F. W. and Fuller , K. R. 1992 . Rings and Categories of Modules , 2nd Ed.; Graduate Texts in Mathematics Vol. 13 , New York : Springer-Verlag .
- Cohen , M. , Fischman , D. and Montgomery , S. 1992 . Hopf Galois Extensions, Smash Products and Morita Equivalences . J. Algebra , 133 ( 2 ) : 251 – 272 .
- Dade , E. C. 1980 . Group-Graded Rings and Modules . Math. Z. , 174 ( 3 ) : 241 – 262 .
- Haefner , J. 1996 . On When a Graded Ring is Graded Equivalent to a Crossed Product . Proc. Amer. Math. Soc. , 124 ( 4 ) : 1013 – 1021 .
- Haefner , J. and del Río , A. 1999 . Actions of Picard Groups on Graded Rings . J. Algebra , 218 ( 2 ) : 573 – 607 .
- Krempa , J. and Okniński , J. 1980 . Semilocal, Semiperfect and Perfect Tensor Products . Bulletin de l'Académie Polonaise des Sciences , XXVIII ( 5–6 ) : 249 – 256 .
- Lam , T. Y. 1991 . A First Course in Noncommutative Rings , Graduate Texts in Mathematics Vol. 131 , New York : Springer-Verlag .
- Montgomery , S. 1993 . Hopf Agebras and Their Actions on Rings , CBMS Regional Conference Series in Mathematics, Amer. Math. Soc. Vol. 82 , Providence, R.I.
- Ştefan , D. 1996 . Cohomology of Hopf Algebras and the Clifford's Extension Problem . J. Algebra , 182 ( 1 ) : 165 – 182 .