> ## Documentation Index
> Fetch the complete documentation index at: https://docs.metriport.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Reference

> Base StructureDefinition for Reference Type: A reference from one resource to another.

## Properties

| Name | Required | Type | Description |
| - | - | - | - |
| id | No | string | Unique id for inter-element referencing |
| extension | No | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations |
| reference | No | string | Literal reference, Relative, internal or absolute URL |
| type | No | uri | Type the reference refers to (e.g. "Patient") |
| identifier | No | [Identifier](/medical-api/fhir/data-types/identifier) | Logical reference, when literal reference is not known |
| display | No | string | Text alternative for the resource |


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