This Technical Report covers aspects of federations of Clinical Document Registries (CDRs) including cases where the whole content of a CDR has been replicated in another CDR of the same federation. More specifically, the following aspects are covered. a) Recommendations for the creation and management of federations of CDRs and federation metadata. b) Creation and management of federated replicas, including specifications to create, remove and maintain federated replicas as well as metadata for them. c) Use cases of federations with query processing examples, including various use cases of federations of CDRs, together with examples of query processing policies to enhance the performance and fault-tolerance. d) Processing of queries in the presence of federations and replicas: the presence of federated replicas might affect the semantics of both local and federated queries. Informative examples to define exact behaviours of processing the queries are given.