I need sources for quotes, where do I go?

So for a story I've recently started back up, every chapter starts with a quote and I want to get the original source for these and I have no idea how to do this.
I used to browse through the bumper stickers on Facebook and copy the ones I liked or I thought would fit into my story onto paint and then later onto a word document. I know where a few of them originally came from and who originally said them, but most I don't.
So what I want to know is, is there some kind of database or site that can help me figure this out? Just typing the quote into google doesn't really do much.
Thanks much

Funny I was about to suggest using Google. Actually, there's plenty of such databases on the Internet. Google "quotes" or "quotations" and a ton of sites will come up. Pick one, type your quote and see if it shows up. I would double check with another site as well to make sure the same source comes up, just in case one comes up wrong.

If nothing comes up on any of the sites, it might be okay to put "Source unknown". I'm pretty sure I've seen that before, but it might just be for really old quotes that no one ever cited so no one knows who said it.

I use www.quotegarden.com you can type in a search on there and there will be quotes related to a certain topic.