CC URL
Archival Resource Key (ARK): ARK is an identification scheme for a persistent identifier for information objects. Using the optional "Qualifier" part, a kind of service entry point could be created that allows an ARK to support access to variants (versions, languages, formats) of components by using the '.' (period) character after the Name part of an ARK. For example, the URI https://api.istex.fr/ark:/67375/6GQ-MLC8GRWC-5 list all the variants and the PDF variant is at the URI https://api.istex.fr/ark:/67375/6GQ-MLC8GRWC-5/fulltext.pdf.
URL path extension (suffix pattern matching): this approach is similar to the ark approach, which is to use the URI with an extension primarily to request the media type of API endpoints. The URI http://myapi.example.com/account/123.json would provide the 123 account in a json format.
Query String Arguments (QSA): A query string is a part of a URL which assigns values to specified parameters. QSAs are commonly used to deliver extra information to a server. One of which is preferences to select an appropriate variant http://linked.data.gov.au/dataset/gnaf/address/GAACT714845933?_view=ISO19160&_format=text/turtle.