If a non-free copyrighted source is being used, it is recommended to use original language and direct quotations, to clearly separate source material from original material; nevertheless, limited close paraphrasing may be acceptable under fair use in some cases.
It is recommended to use original language, to clearly separate source material from original material. It is recommended to use direct quotations, to clearly separate source material from original material. A non-free copyrighted source is being used. Limited close paraphrasing may be acceptable under fair use in some cases. This is nevertheless.