Understanding Relationships in E-R Diagrams

Few articles about E-R diagrams worth to read:

Understanding Relationships in E-R Diagrams (part 1, 2, 3)
Documenting Entities, Attributes & Relationships
E-R Diagram Relationship Integrity Constraints
Interpreting Cardinality and Dependency on an E-R Diagram
Guidelines for Naming E-R Attributes
Recursion in E-R Relationships
Notations on Entity-Relationship Models
Entity-Relationship Diagram Checklist