Some feature suggestions

Some feature suggestions (I hope they're not too redundant with others on the site):

1. Some kind of history buttons. I use it in church, and when we go to a reference, it would be nice to be able to jump back.
2. Being able to set up a parallel between bibles and commentaries. If I'm reading a bible, I'd like to be able to switch to a commentary to see what it says, but it is often difficult to get there, so I don't bother. Different versions of the Bible already seem to do this. 
3. Search filters. Being able to narrow the search to Old or New Testament at minimum; to a certain book or range would be better. Sometimes so many results are returned it's not worth working through.