↑Barrow, J. D. (1999). Impossibility: The Limits of Science and the Science of Limits. Oxford University Press. p. 14.
↑Freud E, Ganel T, Avidan G. Representation of possible and impossible objects in the human visual cortex: Evidence from fMRI adaptation. NeuroImage. 2013 Jan 1;64:685-92.
↑Aigner, Martin; Ziegler, Günter M. (2018). "Chapter 15: The Borromean Rings Don't Exist". Proofs from THE BOOK (第6版). Springer. pp. 99–106. doi:10.1007/978-3-662-57265-8_15. ISBN978-3-662-57265-8. {{cite book}}: More than one of |author1=、|last1= specified (help); More than one of |author2=、|last2= specified (help)