1. Where ever possible HL7 artifacts that reference coded content should use externally managed, established, curated concepts made available as a versioned code system (or can be a subset of said code system) that is
    1. Follows good vocabulary practices as defined by HL7 e.g.
      1. Have definitions for each concept and the relationships it uses
      2. Uses meaningless identifiers
      3. Manages synonymy
    2. Under the curation of an established organization that is committed to maintaining the code system content, i.e. a terminology authority (see also ISO/TR 12309:2009 Health informatics -- Guidelines for terminology development organizations) and particularly
      1. Either provide, or work with HL7 to establish an identifier for the code system
      2. Provide a current human contact for the content and a link to a source for the content
    3. Has established processes for content improvement
    4. Has straightforward licensing requirements
    5. Provides easy access to the code system content, either directly or through shared terminology services, including having the current version available to support publishing and maintenance of those published artifacts
    6. Is well established for use to describe the concepts in question (i.e. well established for use in the context of the concept domain)
    7. If alternatives are available, code systems that have low or no cost for use are preferable
  2. Any publication or draft HL7 specification or implementation guide that references an external code system in any way must:
    1. Clearly identify the external content governed by IP restrictions beyond those of HL7
    2. Provide a web-link to the licensing information for the content and/or provide a short description of the requirements
    3. Reference the code system version when the artifact is published, and whether the version for use is important for the artifact
    4. If translations are involved...???
    5. Include, at minimum the following statement, prominently placed (e.g., black box warnings at the begining of Structured Product Labels in the United States) :
      "This HL7 specification contains and references intellectual property owned by third parties ("Third Party IP"). Use of any HL7 specifcation and it's associated licensing terms does not grant any rights with respect to Third Party IP. The licensee alone is responsible for identifying and obtaining any necessary licenses or authorizations to utilize Third Party IP in connection with the specification or otherwise."