code: func (r ReferenceStorage) Reference(n plumbing.ReferenceName) (*plumbing.Reference, error) {
  	if _, deleted := r.deleted[n]; deleted {
  		return nil, plumbing.ErrReferenceNotFound
  	}
  
  	ref, err := r.temporal.Reference(n)
  	if err == plumbing.ErrReferenceNotFound {
  		return r.ReferenceStorer.Reference(n)
  	}
  
  	return ref, err
  }
docs: // Reference honors the storer.ReferenceStorer interface.