Gustavo Arechavaleta Jean-Paul Laumond Halim Hicheur Alain Berthoz An Optimality Principle Governing Human Walking. 5-14 2008 24 IEEE Transactions on Robotics 1 http://dx.doi.org/10.1109/TRO.2008.915449 db/journals/trob/trob24.html#ArechavaletaLHB08