The literatures status can be labeled with “read” or “unread” automatically by certain marks or colors. For example, I downloaded or imported some literatures from the web, all of them will be labeled with “unread” , after the click on the titile, it will change into “read” automatically. And the user can also change the status manually.
The user can label the literature with its importante or useage or something like this. And the level could be found by a glance on the literature (for example, from one star to five star to distinguish the importance of the literatures). This is helpful in review the literatures.