http://books.google.co.in/books?id=busgee_YN3oC&printsec=frontcover&dq=Modern+Control+System+Theory+%E2%80%93+by+M.+Gopal&source=bl&ots=SbwQfISipX&sig=K2gl0ssbCGDRPu13yEChFe7MBtE&hl=en&ei=aVXiTI_EBpG2sAOS461m&sa=X&oi=book_result&ct=result&redir_esc=y for acs pa.................