http://www.chem.ucla.edu/~webspectra/
https://www3.nd.edu/~smithgrp/structure/workbook.html
http://www-usr.rider.edu/~grushow/nmr/NMR_tutor/selftests/problems_fs_start.html
http://www.chem.ucalgary.ca/courses/350/Carey5th/Ch13/isp/index.html