https://core.ac.uk/download/pdf/42874579.pdf
https://www.youtube.com/watch?v=dRiCn6clquA&list=PL4DfcQ32obJaEqNwW6qopYqm07AqLZCXM&index=17
https://www.youtube.com/watch?v=snbFjwXTEI8&list=PL4DfcQ32obJaEqNwW6qopYqm07AqLZCXM&index=16
https://www.youtube.com/watch?v=jtDyt6etmhk&list=PL4DfcQ32obJaEqNwW6qopYqm07AqLZCXM&index=15
https://www.youtube.com/watch?v=Cr6tnMBbMRw&list=PL4DfcQ32obJaEqNwW6qopYqm07AqLZCXM
https://www.youtube.com/watch?v=gK5g8Q3FlH4