getTopicReference(referenceId) {
        if (this.references[referenceId] === undefined) {
            this.references[referenceId] = new HassAnchor({type: HassAnchor.TYPE.REFERENCE, subType: referenceId});
        }

        return this.references[referenceId];
    }
Retrieve an instance for an anchor.

@public
@param {string} referenceId
@return {HassAnchor}