So I have few lines in my book straight from Wikipedia. What is the best way to quote them? Will them be any problem when I l buy the copyrights?
Wikipedia is open source...not sure how you would buy copyrights to public material. That being said, while Wikipedia is a good springboard to start research, I wouldn't quote it in any serious work I was writing. When it is a document anyone can edit, the information is not always correct and I would look for source documents from respected sources before I would quote Wikipedia. Usually, for each claim made in a wiki article, there is a reference number that looks like [1], if you click on that it should take you to the article the claim was pulled from, and if I were you, I would start there.
How to cite to Wikipedia: https://www.scribbr.com/citing-sources/how-to-cite-wikipedia/ If you think you're using more than what is allowed by Fair Use, it is worth looking at the licenses that Wikipedia gives to its content. Sometimes, such licenses require that the work incorporating the open content be released under the same terms, or less restrictive terms. I haven't looked at their licenses, but depending on what they say they could affect your own rights in a work that incorporates Wikipedia content (again, assuming we're not talking about a Fair Use).
What do you mean "buy the copyrights"? Are you talking about purchasing rights to quote from Wikipedia, or are you referring to registering the copyright to your book? I don't know what country you are in. I'm in the U.S. We don't have to buy copyrights -- our work is automatically copyrighted as soon as we write (or draw) it. However, we can make the copyright stronger by registering the work with the Library of Congress, and there is a fee for doing that. But they don't look through each book to see if the author copied something from another copyrighted work. Joe Hall is pretty much spot on about Wikipedia -- it's hardly a respected source for citations. But, as Mr. Hall pointed out, the better Wikipedia articles are full of citations, and I agree with him that you would probably do better to go to the source(s) cited in the Wiki article. And the Wiki article should show you how to cite it, as well. Look at the footnotes.
Wikipedia is an extremely unreliable source. I once checked the entry for "Taliban" and the article was quite favorable, obviously written by a Taliban flack. There was no mention that they've destroyed ancient Buddha statues, or that they terrorize people who try to educate girls.
