- Ph.D. thesis:
Idealizers in free algebras,
University of London, 1974.
- Ph. D. theses (co-)directed:
- M. C. Hedges,
One-relator graded algebras,
University of London, 1986.
- E. Ventura,
Endomorfismes de grups lliures finitament generats,
Universitat Autònoma de Barcelona, 1995.
- M. Chas,
Minimum periods of homeomorphisms of orientable surfaces,
Universitat Autònoma de Barcelona, 1998.
- L. Bacardit,
Algebraic mapping-class groups of surfaces with one boundary component,
Universitat Autònoma de Barcelona, 2009.
- Y. Antolín
On a class of two-relator groups,
Universitat Autònoma de Barcelona, 2010.
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