paper by Helmut Brandl Intuitionistic Type Theory notes by Per Martin-Löf Programming in Martin-Löf ’s Type Theory book Homotopy Type Theory book, which proposed homotopy type theory as a mathematical foundation. Advanced material The TYPES Forum — moderated e-mail forum focusing on type theory in computer science, operating since 1987. The Nuprl Book: "Introduction to Type Theory." Types Project lecture notes of summer schools 2005–2008 The 2005 summer school has introductory lectures Oregon Programming Languages Summer School, many lectures and some notes. Summer 2013 lectures including Robert Harper's talks on YouTube Summer 2015 Types, Logic, Semantics, and Verification Andrej Bauer's blog Systems of formal logic Hierarchy