Q: how do I recover deleted pages09 app

I have deleted the earlier version of Pages but need it now as older documents want to be opened in 09 before they can be edited or read in 5.1. The procedure is a pain as it surely wouldn't have been beyond the skills of Apple to set up a translater routine in the newer version of Pages, something I had assumed would be there.

So as I previously owned a copy of Pages09 how can I recover it? It is not listed in the App Store of course, nor in my long list of purchases.