Legal Question in Intellectual Property in California

It Depends. Whether or not you actions violate copyright law does not necessary depend on whether you disclose the source of the quotes.

Whether you a violating copyright will depend on a number of factors, including whether you have a license to the quotes, whether your use fall under fair use and whether or not the quotes are already in the public domain.

It does not matter that the quotes are famous or not, or whether you are giving credit to the authors. If you did not have permission to use the quotes and your use does not fall under fair-use, it is likely that you could be sued, especially when you are using it for your business.

You should consult an intellectual property attorney in your area, to review how you are using these quotes and how to proceed.