'List of parameters actually included in the model, in sorted order.
TODO Make this an OrderedDict with slice or indices as the values.'

@property
def param_terms(self):

    model_orders = self.model_orders
    params = [order for order in self.params_complete if (model_orders[order] > 0)]
    if (('exog' in params) and (not self.mle_regression)):
        params.remove('exog')
    return params
