http://en.wikipedia.org/wiki/Chebyshev_filter
http://www-users.cs.york.ac.uk/~fisher/mkfilter/trad.html
http://www-k.ext.ti.com/SRVS/Data/ti/KnowledgeBases/analog/document/faqs/ch.htm
http://users.ece.gatech.edu/mleach/ece3050/f99/cheb.pdf
http://www.engr.uky.edu/~gedney/courses/ee521/notes/Set5_LadderFilterAndPuff.pdf
http://site.iugaza.edu.ps/aliafana/files/2010/04/02_analog_filters.pdf
http://www.dspguide.com/ch20.htm
http://en.wikibooks.org/wiki/Signals_and_Systems/Filter_Implementations
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3265070/
http://www.rfcurrent.com/gencheb
http://eceweb1.rutgers.edu/~orfanidi/ece521/notes.pdf
http://www.matheonics.com/Tutorials/Chebyshev.html