You may get the PDF for the article (The measurement of organizational commitment) by Richard T Mowday, Richard M Steers & Lyman W Porter through Google Scholar.

Here are some links to a direct download of Moday, Steers, and Lyman (1979):

https://apps.dtic.mil/dtic/tr/fulltext/u2/a057377.pdf

https://www.researchgate.net/profile/Ibrahim_Neziri/post/Can_anyone_recommend_an_instrument_scale_for_measuring_leadership_styles_and_employee_commitment/attachment/59d6420679197b807799ddac/AS:437306260758529@1481273345397/download/Junaid.pdf

You can get it on google scholar.

kindly find attached PDF file

Dear Fatma, just a quick hint that you should check if the OCQ is adequate for your reserach interest and have a look at possible alternatives (e.g., https://u.osu.edu/commitmentmeasure/)