anchor.diff:          
   
   
  -### Create a new Media for an existing Work [POST]
  -
  -Create a new Media instance and link it to the Work.
  -
  -Only the following properties in the request will be used:
  +### Create or link a Media to an existing Work [POST]
  +
  +If `href` is included, the referenced `Media` instance will be linked to this work.
  +
  +Otherwise a new Media instance is created and linked to this work, 
  +using the following properties in the request:
   
   - annotations (empty list if omitted)
   - metadata (empty object if omitted)
   - replaces (null if omitted)
   
   + Request (application/json)
  -    [Media][]
  +    
  +        {
  +            "replaces": {
  +                "href": "https://catalog.elog.io/works/5396e592d7d163613d7321ee/media/oldMediaID"
  +            },
  +
  +            "annotations": [{
  +                    "property": {
  +                        "propertyName": "title",
  +                        "value": "Title of the work",
  +                        "titleLabel": "Title of the work"
  +                    }
  +                }],
  +            "metadata": {
  +                "oembed": { "url": "http://some/photo.jpg" }
  +            }
  +        }
       
   + Response 201 (application/json)
       [Media][]
  
positive.code:     [Media][]
  
  
  ## Media collection [/works/{workID}/media{?annotations}]
  
  All the Media instances linked to this work.
  
  + Parameters
      + workID (string) ... Work ID whose Media are manipulated
      + annotations (string, optional) ... Select properties to get in response.
  
  ### List Work Media [GET]
  
negative.code: The API uses many ideas from 
  https://github.com/interagent/http-api-design and https://developer.github.com/v3/
  
  Referenced objects are returned as a map:
  
      {
          "id": "someUserID",
          "href":  "https://catalog.elog.io/users/someUserID"
      }
      
  When referencing another object in a PUT or POST request either property can be used for top-level objects,
  but for e.g. `Media` objects that are referred via a `Work` only `href` is possible.
  
  
  ## Work [/works/{workID}{?fields,include,annotations}]
  A work record.
  
  The annotations, media and sources can either be manipulated via the sublist in the document, 
  