Hi Mary, I don't know off the top of my head, but as a suggestion you could just use an open book (with the crease) element, desaturate the colour and enlarge to the size you would need? This is an example I just roughly put together to show you what I mean. The element and paper are from Vicki Robinson's
Teachable Moments Kit
If anything else comes to mind I will pop back and let you know and perhaps someone else may know of an overlay as well.
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)