OK, here's a site: http://www.stacksandstacks.com/html/90047_bookcase-folding.htm

I found another site that mentioned they could be purchased at Target. Note that you can buy them 3 shelves high and stackable. That would give ya 6 shelves, in case you have trouble with math. Most of mine came folded up individually in their own boxes, so would be easy to ship.

A fish and a bird can fall in love, but where will they build their nest?