MathLinks theory http://users.pandora.be/educypedia/education/mathcomplex.htm http://www.ping.be/~ping1339/complget.htm the places where you will find the complet theory of complex numbers http://mathworld.wolfram.com/ComplexNumber.html-on this website you can find the most important aspects of complex numbers history If you want to know more anbout the history of complex numbers you ought to visit these websites: http://math.fullerton.edu/mathews/c2003/HistoryComplexBib/Links/HistoryComplexBib_lnk_1.html-where you can find a list of internet resources. http://www.experiencefestival.com/a/Complex_number_-_History/id/1249265 http://rossroessler.tripod.com/ The history of complex numbers from different perspectives. http://digitalcommons.libraries.columbia.edu/dissertations/AAI9985857/ A summary of the mist important moments in the history of complex numbers interactive http://wims.unice.fr/wims/en_home.html Lessons, references, online calculators, interactive exercises await for you on this website http://scholar.hw.ac.uk/site/maths/topic1.asp- Plenty of problems and exercises. http://www.math.uu.nl/people/beukers/voorlichting/CompVis.htm- draw your own complex numbers http://scholar.hw.ac.uk/site/maths/activity7.asp -> substract complex no Interactive software for complex numbers: http://www.mathaid.com/products/Precalculus/index.html Interactive Fourier Transform Experiment http://homepages.inf.ed.ac.uk/rbf/HIPR2/fftdemo.htm Applications of complex numbers in electonics http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/info/signals/complex/cmplx.html