code: func (s *RepositoriesService) ListTrafficReferrers(ctx context.Context, owner, repo string) ([]*TrafficReferrer, *Response, error) {
  	u := fmt.Sprintf("repos/%v/%v/traffic/popular/referrers", owner, repo)
  
  	req, err := s.client.NewRequest("GET", u, nil)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	var trafficReferrers []*TrafficReferrer
  	resp, err := s.client.Do(ctx, req, &trafficReferrers)
  	if err != nil {
  		return nil, resp, err
  	}
  
  	return trafficReferrers, resp, nil
  }
docs: // ListTrafficReferrers list the top 10 referrers over the last 14 days.
  //
  // GitHub API docs: https://developer.github.com/v3/repos/traffic/#list-referrers