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

http://www.ch.ic.ac.uk/harrison/Teaching/ft.pdf

http://en.wikibooks.org/wiki/Circuit_Theory/Fourier_Transform

http://www.thefouriertransform.com/series/circuitExample.php

http://books.google.com/books/about/Schaum_s_Outline_of_Theory_and_Problems.html?id=rIY8edDHHSMC

http://www.ece.rutgers.edu/~psannuti/ece224/PEEII-Expt-6-07.pdf

http://my.safaribooksonline.com/book/electrical-engineering/9780470633229/basic-engineering-circuit-analysis-tenth-edition/chapter_15_fourier_analysis_te

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