Nonlinear and optimal control theory : lectures given at the C.I.M.E. Summer School held in Cetraro, Italy, June 19-29, 2004 / Andrei A. Agrachev, A. Stephen Morse, Eduardo D. Sontag... [et al.] ; editors, Paolo Nistri, Gianna Stefani / Berlin, Heidelberg : Springer Berlin Heidelberg