Add links to the OAuth 2.0 homepage for reference (fixes #306) (#373)

Author: kpshek

docs/specification/1.0.md

@@ -111,7 +111,7 @@ Field | Optionality | Type | Description
 `hook` | REQUIRED | *string* | The hook that triggered this CDS Service call<br />(todo: link to hook documentation)
 <nobr>`hookInstance`</nobr> | REQUIRED | *string* | A UUID for this particular hook call (see more information below)
 `fhirServer` | OPTIONAL | *URL* | The base URL EHR's [FHIR](https://www.hl7.org/fhir/) server. If fhirAuthorization is provided, this field is REQUIRED.  The scheme should be `https`
-`fhirAuthorization` | OPTIONAL | *object* | A structure holding an OAuth 2.0 bearer access token granting the CDS Service access to FHIR resources, along with supplemental information relating to the token. See the [FHIR Resource Access](#fhir-resource-access) section for more information.
+`fhirAuthorization` | OPTIONAL | *object* | A structure holding an [OAuth 2.0][OAuth 2.0] bearer access token granting the CDS Service access to FHIR resources, along with supplemental information relating to the token. See the [FHIR Resource Access](#fhir-resource-access) section for more information.
 `user` | REQUIRED | *string* | The FHIR resource type + id representing the current user.<br />The type is one of: [Practitioner](https://www.hl7.org/fhir/practitioner.html), [Patient](https://www.hl7.org/fhir/patient.html), or [RelatedPerson](https://www.hl7.org/fhir/relatedperson.html).<br />For example, `Practitioner/123`
 `context` | REQUIRED | *object* | Hook-specific contextual data that the CDS service will need.<br />For example, with the `medication-prescribe` hook this will include [MedicationOrder](https://www.hl7.org/fhir/medicationorder.html) being prescribed.  For details, see the [Hooks specification](http://cds-hooks.org/hooks/).
 `prefetch` | OPTIONAL | *object* | The FHIR data that was prefetched by the EHR (see more information below)
@@ -293,7 +293,7 @@ The CDS Service is able to use the EHR's FHIR server to obtain any FHIR resource
 
 Like SMART on FHIR, CDS Hooks requires that clients present a valid access token to the FHIR server with each API call. Thus, a CDS Service must be able to obtain an access token before communicating with the EHR's FHIR resource server. While CDS Hooks shares the underlying technical framework and standards as SMART on FHIR, the CDS Hooks workflow must accommodate the automated, low-latency delivery of an access token to the CDS service.
 
-With CDS Hooks, if the EHR wants to provide the CDS Service direct access to FHIR resources, the EHR creates an access token prior to invoking the CDS Service, passing this token to the CDS Service as part of the service call. This approach remains compatible with OAuth 2.0's bearer token protocol while minimizing the number of HTTPS round-trips and the service invocation latency. The EHR remains in control of creating an access token that is associated with the specific CDS Service, user, and context of the invocation.  As the CDS Service executes on behalf of a user, the data to which the CDS Service is given access by the EHR MUST BE limited to the same restrictions and authorizations afforded the current user. As such, the access token SHALL BE scoped to:
+With CDS Hooks, if the EHR wants to provide the CDS Service direct access to FHIR resources, the EHR creates an access token prior to invoking the CDS Service, passing this token to the CDS Service as part of the service call. This approach remains compatible with [OAuth 2.0's][OAuth 2.0] bearer token protocol while minimizing the number of HTTPS round-trips and the service invocation latency. The EHR remains in control of creating an access token that is associated with the specific CDS Service, user, and context of the invocation.  As the CDS Service executes on behalf of a user, the data to which the CDS Service is given access by the EHR MUST BE limited to the same restrictions and authorizations afforded the current user. As such, the access token SHALL BE scoped to:
 
 - The CDS Service being invoked
 - The current user
@@ -304,11 +304,11 @@ The access token is specified in the CDS Service request via the OPTIONAL `fhirA
 
 Field | Optionality | Type | Description
 ----- | ----- | ----- | -----------
-`access_token` | REQUIRED | *string* | This is the OAuth 2 access token that provides access to the FHIR server.
+`access_token` | REQUIRED | *string* | This is the [OAuth 2.0][OAuth 2.0] access token that provides access to the FHIR server.
 `token_type`   | REQUIRED | *string* | Fixed value: `Bearer`.
 `expires_in`   | REQUIRED | *integer* | The lifetime in seconds of the access token.
 `scope`        | REQUIRED | *string* | The scopes the access token grants the CDS Service.
-`subject` | REQUIRED | *string* | The OAuth 2.0 client identifier of the CDS Service, as registered with the EHR's authorization server.
+`subject` | REQUIRED | *string* | The [OAuth 2.0][OAuth 2.0] client identifier of the CDS Service, as registered with the EHR's authorization server.
 
 The scopes granted to the CDS Service via the `scope` field are defined by the [SMART on FHIR specification](http://www.hl7.org/fhir/smart-app-launch/scopes-and-launch-context/).
 
@@ -408,7 +408,7 @@ Field | Optionality | Type | Description
 <nobr>`label`</nobr>| REQUIRED | *string* | Human-readable label to display for this link (e.g. the EHR might render this as the underlined text of a clickable link).
 `url` | REQUIRED | *URL* | URL to load (via `GET`, in a browser context) when a user clicks on this link. Note that this may be a "deep link" with context embedded in path segments, query parameters, or a hash.
 `type` | REQUIRED | *string* | The type of the given URL. There are two possible values for this field. A type of `absolute` indicates that the URL is absolute and should be treated as-is. A type of `smart` indicates that the URL is a SMART app launch URL and the EHR should ensure the SMART app launch URL is populated with the appropriate SMART launch parameters.
-`appContext` | OPTIONAL | *string* |  An optional field that allows the CDS Service to pass context regarding the launch of this SMART app from the CDS card to the SMART app. The `appContext` field should only be valued if the link type is `smart` and is not valid for `absolute` links. The `appContext` field and value will be sent to the SMART app as part of the OAuth 2 access token response, alongside the other launch context when the SMART app is launched.
+`appContext` | OPTIONAL | *string* |  An optional field that allows the CDS Service to pass context regarding the launch of this SMART app from the CDS card to the SMART app. The `appContext` field should only be valued if the link type is `smart` and is not valid for `absolute` links. The `appContext` field and value will be sent to the SMART app as part of the [OAuth 2.0][OAuth 2.0] access token response, alongside the other launch context when the SMART app is launched.
 
 ### Example
 
@@ -592,3 +592,4 @@ As another example, an extension defined on the discovery response could look li
   ]
 }
 ```
+[OAuth 2.0]: https://oauth.net/2/