INPOP08, a 4-D planetary ephemeris: from asteroid and time-scale computations to ESA Mars Express and Venus Express contributionsA. Fienga, J. Laskar, T. Morley, H. Manche, P. Kuchynka, C. Le Poncin-Lafitte, F. Budnik, M. Gastineau and L. SomenziA&A, 507 3 (2009) 1675-1686DOI: https://doi.org/10.1051/0004-6361/200911755