Google Documents List APIは2015/04/20までのサポート

Google Documents List API version 3.0 - Google Apps — Google Developers

Warning: The deprecation period for Version 3 of the Google Documents List API is nearly at an end. On April 20, 2015, we will discontinue service for this API. This means that service calls to the API are no longer supported, and features implemented using this API will not function after April 20, 2015. You must migrate to the Drive API as soon as possible to avoid disruptions to your application.