iCloud Storage Bar

When I view the iCloud Storage Bar associated with my account, I see ~4 MB of storage associated with a 'Documents' label. Where can I find what these are? There a couple of notes stored and one reminder but other than mail, calendar info, contacts and photos, I don't see any other records that i keep on my iPhone or iPad available on iCloud. I do have a number of books stored on my iPad and I assumed that these would be available on the cloud (need to confirm settings on my iPad to confirm this) but I can't locate these. If they are stored on the cloud where would I find them.

It's just odd that the storage bar is not live so that i could simply click on the categories listed and the associated files would be shown. Anyway, I'm just trying to find out where I can locate the 3.75 MB of document files that the Storage Bar says I have available on my iCloud account. Any help is appreciated here.