Hello,
I think you should check in google because every thing is available. But just to help you a bit these are the few sites you can check like Kumardarpan.com, Indiamart, google docs. You can even check in playstore often some apps are available. I am sure that you will get the pdfs in the aforementioned sites.
Hope it helps.
good luck.
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile