- excel is in https://github.com/phvu/misc/blob/master/viterbi/JurafskyMartinHmmDecode.xlsx
- penn format: http://www.clips.ua.ac.be/pages/mbsp-tags
- lbfgs, numpy, scipy (allowed): https://docs.scipy.org/doc/#fmin_l_bfgs_b
- these tokens in POS files: ( ) [ ] { } become, in parsed files: -LRB- -RRB- -RSB- -RSB- -LCB- -RCB-