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2. Transfer Functions, Poles and Zeros https://www.maplesoft.com/content/Engineering- Fundamentals/10/MapleDocument_10/Transfer%20Functions,%20Poles%20and%20Zeros.pdf.
3. Understanding Poles and Zeros. [Massachusetts Institute of Technology Department of Mechanical Engineering]. Part 2.14 - Analysis and Design of Feedback Control Systems - http://web.mit.edu/2.14/www/Hand- outs/PoleZero.pdf.
4. John J. D'Azzo, Constantine H. Houpis, Stuart N. Sheldon. Linear Control System Analysis and Design with MATLAB. Fifth Edition, Revised and Expanded. Copyright © 2003 by Marcel Dekker, Inc. - New York, Basel [ISBN: 0-8247-4038-6].
5. W. Bolton. Control Systems. - Elsevier, 2002. [ISBN: 9780750654616].