Number of hours and/or work schedule/full-time hours not mention on the reference letter

[iloveblue_violet]

In my reference letter for my foreign work experience, my work schedule is fixed as Monday to Friday from 8 am to 5pm. But there's no number of hours a week, no work schedule or full time hours mentioned on the employment certificate, how can I proof it? On the certificate of employment it shows the montly salary and on the pay stub as I get paid every 15th and 30th? What should I do? Thanks.