org/licenses/by-sa/3.0CC BY-SA 3.0 Creative Commons Attribution-Share Alike 3.0 truetrue English Martin Veltman in the Gentleman's Club painted by Marike Bok, 1995
http://nuclear.ucdavis.edu/~tgutierr/files/stmL1.html, ontleend aan MartinusVeltman: Diagrammatica: The Path to Feynman Diagrams (Cambridge Lecture Notes