The Editors of Encyclopaedia (updated 2021). “Sebastiano Serlio, Italian Architect”. Britannica. Page 1, Architecture and Visual Arts. https://www.britannica.com/art/Mannerism
Sebastiano Serlio on Architecture, Books VI and VII of ‘Tutte l’opere d’architettura et prospettiva’. New Haven & London, Yale UP (2001) pp. 157-385 (Eng. trans.). http://architectura.cesr.univ-tours.fr/Traite/Notice/ENSBA_Gonse479.asp?param=en