Forum Moderators: not2easy
You're safe with Shakespeare, Voltaire, Michelangelo, etc and most quotes in general. Start quoting entire passages from a Harry Potter book and you might run into trouble.
<added /> You can't use that compilation in toto. They've done the work. You need to compile your own quote collection.
P.S. There is no such thing as "copywritting". You mean "copyright". Which isn't a verb anyway.
1) The mistaken word was "copywriting" (or, more precisely, "copywritten"). IOW, the wrong word was used, but it was not misspelt.
2) There IS such a thing as "copywriting", and people who work as "copywriters", writing sales copy.
3) "Copyright" can indeed be used as a verb. It means "to secure the copyright [noun] to".
(Moral: Before you begin to pick nits, have your own head checked!)
I'll add the comment that depending on the classic work, a particular translation or linguistic style (e.g., conversion from archaic usage to more modern usage) might be used. Even though the classic work might be in the public domain, the translation or other modification of the original may be covered by a more recent copyright.