If you are trying to track down a particular song, but not having any luck, try consulting a song index! Song indexes are useful for locating songs in larger anthologies or collections that you might not have thought to look in.
Refer to the print resources recommended below (you can find all of these at MPAL) or check out the online song indexes listed at the bottom of the page. You may need to try searching in multiple places, so don't give up if the first source you try doesn't work!