This page is part of the US Core (v3.1.1: STU3) based on FHIR R4. The current version which supercedes this version is 5.0.1. For a full list of available versions, see the Directory of published versions 
USCore
The official URL for this implementation guide is:
http://hl7.org/fhir/us/core/ImplementationGuide/hl7.fhir.us.core
