http://home.engineering.iastate.edu/~alexs/classes/2011_Spring_585X/final_projects/Zundel_project.pdf
http://asa.scitation.org/doi/abs/10.1121/1.1901995
http://slis.tsukuba.ac.jp/~terasawa.hiroko.ka/Papers/Terasawa2006_SAPA.pdf
https://www.researchgate.net/publication/259384692_Instrument_Timbre_Characterization_based_on_Chroma_Contours_ChromaTimbre
https://www.mcgill.ca/mpcl/files/mpcl/peeters_2011_jasa.pdf