signal and system book by simon haykin

U can download e-book of signal system by simon haykin from link

https://docs.google.com/file/d/0B8lDery-ZA7XblcwZU9PVWFtY2s/edit

But it is a file with djvu extension so to open this file u have to download a small software from link

https://docs.google.com/file/d/0B8lDery-ZA7XRzB0Qy1QVWFhYjg/edit