I have no idea if I'm asking this in the right place on your blog, but I'm going to ask it anyway. I have written a novel and in that novel I quote one line from Anne of Green Gables. I'm a first timer and though I've tried to figure out exactly what I need to do, I can't find a specific guideline on if I need to cite this, and more importantly, how to do that. I do have the address of the Heirs of L.M. Montgomery and can use that address if I need to do so. My only fear is that they will laugh in my face since it's only one line. Any suggestions?This is always a tricky path and I prefer to be safe and not sorry. I generally go for the permission when I can find ownership.
Generally, quoting one line of a much larger source is considered "fair use"—under certain conditions. You can read the official U.S. Copyright definition HERE and Wikipedia has a discussion of it HERE.
However, according to Project Gutenberg, Anne of Green Gables is not under copyright protection here in the U.S. so you would be free to use that line without fear.