Narusue, Yoshiaki; Kawahara, Yoshihiro: 'Multi-hop wireless power transmission' (Energy Engineering, 2018), 'Wireless Power Transfer: Theory, technology, and applications', Chap. 4, pp. 37-64, DOI: 10.1049/PBPO112E_ch4
IET Digital Library, https://digital-library.theiet.org/;jsessionid=2pnr242j7u85.x-iet-live-01content/books/10.1049/pbpo112e_ch4