http://web.ist.utl.pt/luis.tarrataca/classes/computer_architecture/Chapter11-DigitalLogic.pdf
https://www.electronics-tutorials.ws/sequential/seq_1.html
https://www.seas.upenn.edu/~cit595/cit595s10/lectures/seqcircuitsPart1.pdf
https://courses.cs.washington.edu/courses/cse370/04wi/pdfs/lectures/06-Sequential.pdf
https://www.cs.ou.edu/~fagg/classes/ame3623_s05/lectures/class_sequential.pdf
http://bwrcs.eecs.berkeley.edu/Classes/icdesign/ee141_f01/Notes/chapter7.pdf
http://www.ece.utah.edu/~kalla/ECE3700/verlogic3_chapter6.pdf
http://www.eecg.toronto.edu/~mdhutton/papers/thesis4.pdf
http://web.ee.nchu.edu.tw/~cpfan/FY92b-digital/Chapter-5.ppt
http://pami.uwaterloo.ca/~basir/ECE124/Sync_Circuit_Analysis_Design.pdf
http://www.pitt.edu/~kmram/0132/lectures/sequential-circuit-analysis.pdf
http://www.ee.ncu.edu.tw/~jimmy/courses/DSD06/05_seq.pdf
http://pages.hmc.edu/harris/cmosvlsi/4e/lect/lect11.pdf
https://www.seas.upenn.edu/~cit595/cit595s10/lectures/seqcircuitsPart1.pdf