As Philip Scott says about Densi Higgs:
In category theory, he wrote an influential and beautiful long paper, "A category approach to Boolean valued set theory", which initiated many early students in topos theory in the 1970s to Omega-valued sets.
I wonder to know if there is a way to get access to the following paper by Higgs:
``A category approach to Boolean valued set theory''
Remarks. I am aware of some similar works, for example A category-theoretic approach to boolean-valued models of set theory or the book Sheaves in geometry and logic by Mac Lane and Moerdijk.