can i use php documentation for my web tutorial

Hello Sir I wish to query that whether i can use the php documentation in my web tutor forum which i intend to create. I had learnt the wonderful php programming language from the very best e-tuturial i ever came across. (PHP documentation in chm format) While i was gaining knowledge through the documentation i came across certain difficulties in understanding certain aspects of PHP. Now after earning some bucks from my php knowledge, i wish to publish PHP web tutorial with a forum facility. For this i think i would be heavily borrowing and referencing users back to the main PHP documentation. The website would be free for anyone. I wish to know can i use the documentation text for my web tutorial forum or are their any restriction. Please revert back soon. With best wishes. GCM