"A reference architecture in the field of software architecture or enterprise architecture provides a template solution for an architecture for a particular domain. It also provides a common vocabulary with which to discuss implementations, often with the aim to stress commonality. " - Wikipedia.
"A reference model is an abstract framework for understanding significant relationships among the entities of some environment, and for the development of consistent standards or specifications supporting that environment. A reference model is based on a small number of unifying concepts and may be used as a basis for education and explaining standards to a non-specialist. A reference model is not directly tied to any standards, technologies or other concrete implementation details, but it does seek to provide a common semantics that can be used unambiguously across and between different implementations." - OASIS
The NIST Cloud Computing Reference Architecture is a detailed example of complete reference architecture. It includes a high level Reference Model along with details about the Actors, interactions and implementation patterns that are best practices for delivery and consumption of cloud services.
EIP Solution Architecture
IAM Brick Diagrams
EBS Solutions Architecture