Where can I research mermaids?

I was watching a TV show Where this one girl got "Captured" by the full moon and she was singing a "mermaid siren". Where can I research mermaids and the sirens if they are real? I want to read about stories of sailors who have "saw" mermaids. Also on this show the one boy said it s a SIREN that lured sailors to their death. I would like websites or Google suggestions or websites where I would be able to read about these things? Thanks in advance!