Backing up PDF's in iBooks from iPad iOS 7 to iTunes 11.4.1
I frequently receive PDF's via email (scientific journal articles). I store them in iBooks, on my iPad, because I like the folder system and easy email functions. How can I ensure these are backup up?
To clarify, my iPad is my primary business device, not my laptop. I receive documents on my iPad email and store them on the iPad so I can share them with my customers. I do not use my iTunes on my PC for anything except backing up my iPad. I do not receive or manage PDF's on my PC, ever. I travel frequently and do not use my laptop.
A few weeks ago my employer created a situation where I had to restore my iPad from backup and ALL my PDF's were lost. This was a very carefully and painstakingly curated library that cannot be easily recreated. This cannot happen again and I am looking for a SIMPLE step-by-step system to ensure the PDF's are backed up should something happen to my iPad again.
Please understand that I am not a programmer etc. just an ordinary user. If someone could help without jargon or assumptions of expertise, that would be most appreciated.
Thank you!
iPad, iOS 7, ITunes in windows 7 PC