Q: Missing iBooks

Hi all,

After a recent restore from Time Machine, I can see missing books from my iBooks collections/list.  When I check my other iMac I can see the books (pdfs actually).  If I search for the PDFs I can find them on the iMac they are missing from under the mobile library directory with the label "iCloud synchronisation file".

Is there a way to force them to be resynced so they can appear in my iBook collections again?

Thanks.