The CBI has sent notice to former Telecom Minister A Raja to appear before it for questioning in connection with the 2G spectrum scam. The move comes after the CBI raided 34 places in Delhi and Tamil Nadu on December 15 and questioned several persons informally. Our correspondent reports, more persons will receive similar notices from the agency, which is investigating the 2G spectrum scam. In the just concluded winter session of the Parliament, the CAG report on 2G spectrum scam was tabled. The report has pegged a huge revenue loss to the exchequer.