RAWALPINDI: National Accountability Bureau (NAB) on Friday filed a supplementary reference against Pakistan Muslim League-Nawaz (PML-N) President Nawaz Sharif in Al Azizia Steel Mills case. According to sources, pertaining directions from NAB Director-General (DG) Irfan Mangi, supplementary references against Nawaz in Azizia Mills and Flagship Investment cases have been filed, while the PML-N spearhead has also been summoned for appearance on Saturday. Moreover, NAB Chairman Javed Iqbal has expressed his displeasure at Punjab government’s lack of cooperation in cases concerning 56 public limited companies. For this purpose, an inquiry is being conducted and NAB had sent four letters to the Punjab government, but received no response, Javed said. The provincial government has, however, dismissed statements of NAB chief, saying that representatives of the governing body are cooperating with the accountability bureau and that records of 47 companies have already been provided.