Title of the book required.

Dear all.

I was reading an elementary book in which it was very clearly explained about the assumeption,  plane remains plane before and after bending.  ( Euler - Bernouli beam theory ).

In that book author clearly explained why the plane should remain plane, what happens if it takes some other shapes like  C shape or S shape. 

I forgotton the books name, I request all that please let me know the title of the book.

Thanks and regards

Vinay