1. Marcovecchio E. Dizionario etimologico storico dei termini medici. Festina Lente: Impruneta; 1993. p. 839.
2. Cytowic RE. Synesthesia. In: A Union of the Senses. Cambridge: MIT Press; 2002.
3. Day SA. Types of synaesthesia; 2021. http://www.daysyn.com/types-of-syn.html. Accessed 21 Dec 2021.
4. Cytowic RE, Eagleman DM. Wednesday is indigo blue: discovering the brain of synesthesia. Cambridge: MIT Press; 2009.
5. Day SA. Synesthesia. In: Demographic aspects of synesthesia; 2021. http://www.daysyn.com/types-of-syn.html. Accessed 21 Dec 2021.