docs: def getReffs(self, textId, level=1, subreference=None):
          """ Retrieve the siblings of a textual node
  
          :param textId: CtsTextMetadata Identifier
          :type textId: str
          :param level: Depth for retrieval
          :type level: int
          :param subreference: CapitainsCtsPassage CtsReference
          :type subreference: str
          :return: List of references
          :rtype: [str]
          """
          passage, inventory = self.__getText__(textId)
          if subreference:
              passage = passage.getTextualNode(subreference)
          return passage.getReffs(level=level, subreference=subreference)