Brunagel 2016, pp. 97–98. Brunagel, François (2016). "Flag Protocol". In Froideville, Gilbert Monod de; Verheul, Mark (eds.). An Expert's Guide to International Protocol: Best Practices in Diplomatic and Corporate Relations (2nd ed.). Amsterdam University Press. pp. 87–123. doi:10.2307/j.ctt20krz43.9. ISBN978-94-6298-105-8. S2CID240858316.
Frynas, Wood & Soares de Oliveira 2003, pp. 57–58. Frynas, Jędrzej George; Wood, Geoffrey; Soares de Oliveira, Ricardo MS (2003). "Business and politics in São Tomé e Príncipe: From Cocoa Monoculture to Petro-State". African Affairs. 102 (406). Oxford University Press on behalf of the Royal African Society: 51–80. doi:10.1093/oxfordjournals.afraf.a138811.
Brunagel 2016, pp. 97–98. Brunagel, François (2016). "Flag Protocol". In Froideville, Gilbert Monod de; Verheul, Mark (eds.). An Expert's Guide to International Protocol: Best Practices in Diplomatic and Corporate Relations (2nd ed.). Amsterdam University Press. pp. 87–123. doi:10.2307/j.ctt20krz43.9. ISBN978-94-6298-105-8. S2CID240858316.