Which URI to use in your RDF?

Guideline 1. Use the data provider URL as your identifier. When the database provider URL uses get arguments sort the arguments in alphabetical order. (Unicode code point order for non ascii URI's)

Guideline 2. Document the URI you use on freebase, to encourage uniformity.  http://www.freebase.com/view/user/biohackathon/default_domain/views/namespace_1

Guideline 3. Document the deprecated or primary URIs.

e.g. the entrez query  http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=22177139 is the same as  http://www.ncbi.nlm.nih.gov/pubmed/22177139 (the community recommend to use the later) or  http://www.ebi.uniprot.org/entry/P05067 is the same as  http://purl.uniprot.org/uniprot/P05067 (where UniProt? asks you use the later, which will give RDF if your HTTP header accepts it).

Guideline 4. When there is more than one official URI for a concept e.g. PDB is available at PDBj, PDBe, RCSB PDB. Then choose the one that you prefer. And add owl:sameAs statements for each URL.