Smart Development Environment Users Guide
- Smart Development Environment (SDE) is UML modeling plug-in seamlessly integrated with most of the leading IDEs in the market.
- http://www.visual-paradigm.com/product/sde/sdejavauserguide.jsp

UML References
- Unified Modeling Language References including version 1.1 to 1.4 (by Visual Paradigm).
- http://umlcenter.visual-paradigm.com/LinksReferences.html

UML 1.4 Diagram Reference
- UML 1.4 Diagrams as quick reference in PDF Format.
- http://www.oio.de/uml-1-4-reference.htm

XML Metadata Interchange Reference
- Aa complete reference which can be downloaded for off-line use, by Zvon.
- http://zvon.org/xxl/XMI/Output/

UML 1.1 Extension for Objectory Process for Software Engineering
- Defines UML extensions for the Rational Objectory Process by Rational.
- http://www.rational.com/media/uml/resources/media/ad970806_UML11_Objectory.pdf

UML 1.1 Extension for Business Modeling
- Defines UML extensions for business modeling, by Rational.
- http://www.rational.com/media/uml/resources/media/ad970807_UML11_Business.pdf

UML 1.1 Notation Guide
- Defines the UML notation and provides examples, by Rational.
- http://www.rational.com/media/uml/resources/media/ad970805_UML11_Notation2.pdf

UML 1.1 Object Constraint Language Specification
- Defines the OCL, which is used to specify the well-formedness of the UML, by Rational.
- http://www.rational.com/media/uml/resources/media/ad970808_UML11_OCL.pdf

UML 1.1 Summary
- An introduction to the UML that provides a road map to the other documents, by Rational.
- http://www.rational.com/media/uml/resources/media/ad970803_UML11_Summary.pdf

UML 1.1 Semantics
- Defines UML in terms of its abstract syntax presented in class diagrams, formal well-formedness rules expressed in OCL, and semantics expressed in text, by Rational.
- http://www.rational.com/media/uml/resources/media/ad970804_UML11_Semantics2.pdf