Ostman, Mats: 'Electrical engineering aspects' (Energy Engineering, 2017), 'Cogeneration: Technologies, Optimization and Implementation', Chap. 4, pp. 49-73, DOI: 10.1049/PBPO087E_ch4
IET Digital Library, https://digital-library.theiet.org/;jsessionid=biaan3lho6i65.x-iet-live-01content/books/10.1049/pbpo087e_ch4