Reference available at a given level

        :param level: Depth required. If not set, should retrieve first encountered level (1 based)
        :type level: Int
        :param subreference: Subreference (optional)
        :type subreference: CtsReference
        :rtype: [text_type]
        :returns: List of levels

def getReffs(self, level=1, subreference=None):
        """ Reference available at a given level

        :param level: Depth required. If not set, should retrieve first encountered level (1 based)
        :type level: Int
        :param subreference: Subreference (optional)
        :type subreference: CtsReference
        :rtype: [text_type]
        :returns: List of levels
        """
        if self.depth is not None:
            level += self.depth

        return self.getValidReff(level, subreference)