http://www.qiau.ac.ir/Services/elearning/zebardast/CTR08.pdf

http://aminnima2.persiangig.com/document/madar1.pdf

http://en.wikipedia.org/wiki/RLC_circuit

http://en.wikibooks.org/wiki/Circuit_Theory/Second-Order_Solution

http://opencourses.emu.edu.tr/file.php/3/Lecture_Notes/second_order_circuits.pdf

http://www.edforall.net/index.php/engineering-a-technology/electrical-a-electronic-eng/141-introduction-to-electronics,-signals,-and-measurement/2653-transient-response-of-second-order-circuits-

http://www.science.smith.edu/~jcardell/Courses/EGR220/slides/L12.pdf

http://ebookbrowse.com/ece-2100-lsn-37-2nd-order-circuits-3-and-exam-prep-pdf-d88157769

http://homepages.wmich.edu/~dlitynsk/ECE%202100%20Lec%20PDF%20final/ECE%202100%20Lsn%2037%202nd%20order%20circuits%203%20and%20exam%20prep.pdf