The Centre will allow residents to fill columns in the National Population Register (NPR) forms on their own through online mode, a month before door-to-door enumeration by Census officials starts. After filling the form online, residents will get a reference code that they could mention to the field enumerator at the time of her/his visit, according to a senior government official. The group of 23 letter writers (G-23), who had written to party chief Sonia Gandhi last August asking for reforms, were not dissenters but protectors of the Congress legacy, senior Congress leader and a key member of G-23, Kapil Sibal, said on Sunday.