Piguet, Christian: 'Ultra-low-power digital design' (Materials, Circuits and Devices, 1996), 'Low-power HF Microelectronics: a unified approach', Chap. 15, pp. 535-582, DOI: 10.1049/PBCS008E_ch15
IET Digital Library, https://digital-library.theiet.org/;jsessionid=q7h8e8m2u0ku.x-iet-live-01content/books/10.1049/pbcs008e_ch15