Holm, Darryl D.Marsden, Jerrold E.Ratiu, Tudor S.2008-11-202008-11-202008-11-20199810.1006/aima.1998.1721https://infoscience.epfl.ch/handle/20.500.14299/31470The Euler-Poincaré equations and semidirect products with applications to continuum theoriestext::journal::journal article::research article