- Topology.
Princeton University Press.
Ryszard Engelking,
General Topology,
Heldermann Verlag,
Sigma Series in Pure Mathematics,
December 1989, ISBN 3-88538-006-4...
- Horst; Strecker,
George E. (2004).
Abstract and
Concrete Categories.
Heldermann Verlag Berlin. Awodey,
Steve (2010).
Category Theory.
Oxford University...
- "Sets, classes, and conglomerates" (PDF),
Category theory (3rd ed.),
Heldermann Verlag, pp. 9–12 abeq2 –
Metamath Proof Explorer, us.metamath.org, 1993-08-05...
- Springer-Verlag. ISBN 0-387-97926-3. Engelking,
Ryszard (1989).
General Topology.
Heldermann Verlag, Berlin. ISBN 3-88538-006-4. Kaplansky,
Irving (2001). Set Theory...
- 2021-10-12.
Willard 1970,
Section 17. Engelking, Ryszard,
General Topology,
Heldermann Verlag Berlin, 1989. ISBN 3-88538-006-4 Kemoto,
Nobuyuki (2004). "Higher...
- [1994] Herrlich, Horst; Strecker,
George E. (2007),
Category Theory,
Heldermann Verlag, ISBN 978-3-88538-001-6. Jacobson,
Nathan (2009),
Basic algebra...
- ISBN 0-387-96980-2. Kravchenko,
Vladislav (2003).
Applied Quaternionic Analysis.
Heldermann Verlag. ISBN 3-88538-228-8. Kuipers, Jack (2002).
Quaternions and Rotation...
- Engelking,
Ryszard (1989).
General Topology.
Sigma Series in Pure Mathematics, Vol. 6 (Revised and completed ed.).
Heldermann Verlag, Berlin. ISBN 3885380064....
- ISBN 978-3-540-64563-4. OCLC 246032063. Engelking,
Ryszard (1989).
General Topology.
Heldermann Verlag, Berlin. ISBN 3-88538-006-4. Kelley, John L. (1975) [1955]. General...
- eds. (1990).
Quasigroups and Loops:
Theory and Applications. Berlin:
Heldermann. ISBN 978-3-88538-008-5. Colbourn,
Charles J.; Dinitz,
Jeffrey H. (2007)...
