Search for titles of items that contain more than one volume.

Mediatype is 'Serial' or 'Newspaper', WHERE COUNT(vid) > 1.

GET /serialtitles?format=api
HTTP 200 OK
Allow: GET, POST, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "error": "unknown query field",
    "error_field": "format",
    "choices_are": [
        "bibid",
        "group_title",
        "aggregationcodes",
        "num_vols",
        "mediatype",
        "spatial_coverage",
        "first_letter",
        "sort_title"
    ]
}