Election of the President: general
Section 132(4) · 1999 Constitution (2004 edition)
What Constitution says
(4) For the purpose of an election to the office of President, the whole of the Federation shall be regarded as one constituency.
This is the 1999 Constitution as published in 2004. Later amendments aren't included yet, so a section may have changed since.
Original source
Official Gazette · CFRN 1999 official PDF · printed page 67. Original document
Release: draft-c8d50d87fae9. Source scope, review and corrections