copy Info:-https://www.bensound.com
2.EDC- Electronic Devices And Circuits:- https://books.google.co.in/books?id=4s0zb4j4r2AC&lpg=PP1&dq=N.salivahan%20suresh%20kumar%20TEXTBOOK%20of%20EDC&pg=PP1#v=onepage&q&f=false
4. SS- Signals and systems:-http://ecerelatedbooks.blogspot.com/2018/03/signals-and-system-full-book-by-ramesh.html?m=1
