Modules for Mathematical Theories (MMT)

In a 2013 journal article titled "A Scalable Module System", Florian Rabe and Michael Kohlhase propose a module system called MMT (Modules for Mathematical Theories) for structuring mathematical knowledge. The paper has a very interesting general discussion of module systems, from programming languages but also other areas like algebraic specification and theorem proving. The system is based on a rather small set of concepts which subsume those of, for example, Standard ML's module system. Thought-provoking!