func (request *XMLSituationExchangeSubscriptionRequestEntry) StopPointRefs() []string {
    if len(request.stopPointRefs) == 0 {
        nodes := request.findNodes("StopPointRef")
        for _, lineRef := range nodes {
            request.stopPointRefs = append(request.stopPointRefs, strings.TrimSpace(lineRef.NativeNode().Content()))