“The novelist as voice hearer” by Patricia Waugh, Professor of English Literature

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)01118-6/fulltext#:~:text=One%20of%20the%20first%20fictional,his%20time%20on%20the%20island.

https://en.wikipedia.org/wiki/Patricia_Waugh

Added 11 a.m.

https://theconversation.com/many-writers-say-they-can-actually-hear-the-voices-of-their-characters-heres-why-139170#:~:text=To%20investigate%20this%20phenomenon%2C%20we,acted%20of%20their%20own%20accord.

https://www.sciencealert.com/most-authors-can-hear-their-characters-voices-in-their-head-and-some-can-talk-with-them-survey-reveals

https://www.theguardian.com/books/2014/aug/22/charles-dickens-hearing-voices-created-his-novels