pdf: http://www.ipt.ntnu.no/~stanko/files/Courses/TPG4230/2020/Lecture_notes/20200207.pdf
video: http://www.ipt.ntnu.no/~stanko/files/Courses/TPG4230/2020/Videos/20200207.mp4
Excel: http://www.ipt.ntnu.no/~stanko/files/Courses/TPG4230/2020/Class_files/20200207/Network_two_gas_wells.xls