http://www.ece.jhu.edu/~cooper/courses/214/signalsandsystemsnotes.pdf

http://www3.nd.edu/~mhaenggi/ee344-04/overview.html

http://www.ee.ic.ac.uk/hp/staff/dmb/courses/DSPDF/00400_Systems.pdf

http://tintoretto.ucsd.edu/jorge/teaching/mae143a/lectures/5fourierseries.pdf

http://www.google.com/url?sa=t&rct=j&q=lti+systems+and+their+properties&source=web&cd=32&cad=rja&ved=0CDUQFjABOB4&url=https%3A%2F%2Fsignal.mit.edu%2Fsystem%2Ffiles%2Flecture12.pdf&ei=-OjmUJSVOIqw0QXr04HwCA&usg=AFQjCNFlcVRJeOVvsXRearc7rKaQO0cjOg&bvm=bv.1355534169,d.d2k

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

http://mathworld.wolfram.com/DiscreteFourierTransform.html

http://www.robots.ox.ac.uk/~sjrob/Teaching/SP/l7.pdf

http://www.google.com/url?sa=t&rct=j&q=Discrete+Fourier+transform+&source=web&cd=10&cad=rja&ved=0CG8QFjAJ&url=http%3A%2F%2Faimm02.cse.ttu.edu.tw%2Fclass%2F91-1%2FFourier%2520Analysis%2FDFT.ppt&ei=Sg_nUKqAJaal0AXSjoCIDw&usg=AFQjCNFX8fB3W5bl4m6sxtdWpgdQmc7j7g&bvm=bv.1355534169,d.d2k

http://en.wikipedia.org/wiki/Discrete-time_Fourier_transform

https://engineering.purdue.edu/~bouman/ece438/lecture/module_1/1.3_fourier_analysis/1.3.3_dtft.pdf

http://www.ee.cityu.edu.hk/~hcso/ee3202_6.pdf

http://www.cems.uvm.edu/~gmirchan/classes/EE275/Mitra_4/examples/AddEx_Ch3.pdf

http://cnx.org/content/m0524/latest/

http://en.wikibooks.org/wiki/Engineering_Tables/DTFT_Transform_Table

http://ocw.usu.edu/electrical_and_computer_engineering/signals_and_systems/8_2node2.html

http://www.google.com/url?sa=t&rct=j&q=dtft+examples&source=web&cd=11&cad=rja&ved=0CDAQFjAAOAo&url=http%3A%2F%2Fwww.ee.lamar.edu%2Fgleb%2Fdsp%2FLecture%252004%2520-%2520Frequency.ppt&ei=TrHnUJGFJoqi4gT6zIC4Ag&usg=AFQjCNFE3Y4VuPDoOWTQXXQ0yaKtWUWQ2g&bvm=bv.1355534169,d.Yms

http://eecs.wsu.edu/~jgraham/files/transform_pairs.pdf