Johnson, D. L. (1980). Topics in the group presentations. Cambridge University.
Cita Chicago (17th ed.)Johnson, David Leroy. Topics in the Group Presentations. Cambridge: Cambridge University, 1980.
Cita MLA (9th ed.)Johnson, David Leroy. Topics in the Group Presentations. Cambridge University, 1980.
Atenció: Aquestes cites poden no estar 100% correctes.