Campbell, C. M. Et Al. 1999. The Semigroup Efficiency of Direct Products of Groups. Proc. Internat. Conf. Semigroups , (Praga, Portugal), 19-25.

Campbell, C. M. , AYIK, H., O'Connor, J. J. , & Ruskuc, N., (1999). The Semigroup Efficiency of Direct Products of Groups . Proc. Internat. Conf. Semigroups (pp.19-25). Praga, Portugal

Campbell, Colin Et Al. "The Semigroup Efficiency of Direct Products of Groups," Proc. Internat. Conf. Semigroups, Praga, Portugal, 1999

Campbell, Colin M. Et Al. "The Semigroup Efficiency of Direct Products of Groups." Proc. Internat. Conf. Semigroups , Praga, Portugal, pp.19-25, 1999

Campbell, C. M. Et Al. (1999) . "The Semigroup Efficiency of Direct Products of Groups." Proc. Internat. Conf. Semigroups , Praga, Portugal, pp.19-25.

@conferencepaper{conferencepaper, author={Colin Matthew Campbell Et Al. }, title={The Semigroup Efficiency of Direct Products of Groups}, congress name={Proc. Internat. Conf. Semigroups}, city={Praga}, country={Portugal}, year={1999}, pages={19-25} }