code: function availableSourcesURL(startDate, endDate) {
  		var url = (baseURL() +'/location/datum/sources?locationId=' +locationId);
  		if ( startDate !== undefined ) {
  			url += '&start=' +encodeURIComponent(sn.format.dateFormat(startDate));
  		}
  		if ( endDate !== undefined ) {
  			url += '&end=' +encodeURIComponent(sn.format.dateFormat(endDate));
  		}
  		return url;
  	}
docs: Get a available source IDs for this location, optionally limited to a date range.
  
  @param {Date} startDate An optional start date to limit the results to.
  @param {Date} endDate An optional end date to limit the results to.
  @returns {String} the URL to find the available source
  @memberOf sn.api.loc.locationUrlHelper
  @preserve