If you notice after syncing your library to another device that you are missing a few articles - it is usually due to articles on your desktop not being resolved (ie. matched with online database credentials). Here's how you fix/find unresolved articles.
1. Search in your library for ".pdf"
2. For those articles - on the left panel you will see headline reading Unmatched Article:
3. Choose "Help ReadCube Resolve Article" and enter a few details about the article and choose the proper reference data.
4. Now click on the sync icon in the top menu of the library view and open your ReadCube app on your other device. You should see the missing files appear.
Still missing files? Please drop us a note at: firstname.lastname@example.org