+ $self->payments($speriod, $eperiod) - $refunded - $expenses;
+}
+
+sub payments {
+ my( $self, $speriod, $eperiod ) = ( shift, shift, shift );
+ $self->scalar_sql("
+ SELECT SUM(paid) FROM cust_pay
+ WHERE ". $self->in_time_period($speriod, $eperiod)
+ );