@techreport{Bok-Cri-Lau-Zid-2008,
    author={Olivier Bokanowski and Emiliano Cristiani and Julien 
           Laurent-Varin and Hasnaa Zidani },
    title={Theoretical and numerical study of HJB approach for space 
           launcher problems },
    year={2008 },
    month={12},
}