ISLAMABAD: In Karkey Rental Power case, the NAB Monday filed a supplementary reference against former prime minister Raja Pervaiz Ashraf and other accused.The NAB prosecutor Waseem Javed submitted the reference in the court. While hearing the case, the NAB court judge Asghar Ali Shah directed the officials to provide copies of reference to the accused and ensure their attendance at the next hearing. The judge adjourned the hearing of the case until July 13.