Back-up, Save and Restore Bookmarks.

Connect up your iOS device to iTunes via the cable.
Select the "Apps" tab to view all apps.
At the end of the page there is the File Sharing area.
Find the app you wish to save the bookmarks from.
Select the two bookmark files "xx.bookmarks" & "xx.bookmarksfolder" (where xx is the title's short name)
Drag them out to save a copy onto your computer.

If the version you have does not show up here (this is the case for a lot of Oxford titles),
　inside of the application's Bookmarks tab,
　 　select "Export & mail" items and email them to your desktop.

Do not rename these files or alter them in any way.

Now find the newest version of the same application in the File sharing area.
Drag the previously saved bookmark files onto the file documents area.
Synch

Your bookmarks should now be copied across to the new application.

You can move the same files to other devices as well or use iCloud to sync them up from this one.

NOTE: This will not work for sharing bookmark lists and folders for different applications.