from his monthly salary. The letter of offer of mortgage finance loan is pleaded and shall be relied upon at the trial. g. In consideration of paragraphs (d) and (e) above, his monthly take home pay is now below N10,000.00." Learned Counsel to the Appellant Adekola Mustapha contended that the Respondent joined issues with the Appellant in her reply to the Appellant's answer to the Petition at pages 25-28 of the Record wherein she admitted the following:"a.That she is aware that the Appellant had parents. b. That she is aware that the Appellant had children from his previous marriage. c. That she is aware of the Appellant shrinking financial status and even went as far as admonishing the Court in that ground not to grant him custody of the child. d. Other averments in paragraphs 6(a) & (b) of the answer to the Petition were not controverted at all." Adekola Mustapha maintained that the Respondent did not deny the Appellant's averments as to his salary on pages 32 and 33 of the Record of Appeal. At pages 34-39 of the Record is the pay slip of the Appellant for six months. Learned Counsel argued that since the Appellant's salary slip is the only proof of income established before the Court, the Court cannot enter any other source of income in favour of the Appellant to justify the award of the maintenance cost. He referred the Court to the case of Savannah Bank Ltd. v. Salami (1996) 8 NWLR Pt. 465 page 131 and submitted that it is the law that oral or extrinsic evidence cannot be admissible to contradict a written document.