1. Bergman, G.: An inner automorphism is only an inner automorphism, but an inner endomorphism can be something strange. Publicacions Matematiques 56, 91–126 (2012)
2. Funk, J., Hofstra, P., Steinberg, B.: Isotropy and crossed toposes. Theor. Appl. Cat. 26, 660–709 (2012)
3. Hofstra, P., Parker, J., Scott, P.J.: Isotropy of algebraic theories. Electron. Notes Theor. Comput. Sci. 341, 201–217 (2018)
4. Hofstra, P., Parker, J., Scott, P.J.: Polymorphic automorphisms and the Picard group. In: Koyayashi, N. (Ed.) 6th International Conference on Formal Structures for Computation and Deduction (FSCD 2021), vol. 195. Dagstuhl Publications LIPlcs (2021)
5. Palmgren, E., Vickers, S.J.: Partial Horn logic and cartesian categories. Ann. Pure Appl. Log. 145, 314–353 (2007)