Which URI to use in your RDF?

Guideline 1: Be polite. Use the data provider's URL as your identifier. Ideally there should be not get arguments, but if there are to avoid ambiguity for string comparison sort them in alphabetical order (e.g.  http://www.example.com/?a=100&b=2 sorting a before b).

Guideline 2. Often a provider offers multiple URLs for the same resource. 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 requests it).

Document the URI pattern you use on freebase, to encourage uniformity. Exact Freebase URL to be confirmed, see  http://www.freebase.com/view/user/biohackathon/

If you want to link to a provider for which the official URL is not clear, document the one you use on Freebase. State that you do not know if it is supported. Other providers should follow this first-come-first-served convention UNTIL the original provide states otherwise (see Guideline 1).

Guideline 3. Sometimes there is more than provider and thus more than one official URI for a record about a common concept, which can happen with consortia. e.g. PDB is available at PDBj, PDBe, RCSB PDB. Then choose the one that you prefer. Consider adding owl:seeAlso references between them, in strong preference over owl:sameAs due that giving misleading semantics.