Ballot, J. Stellar Astrophysics, MPI for Astrophysics, Max Planck Society;
Ballot, J., Jiménez-Reyes, S. J., & García, R. A. (2006). How GOLF sees the second Helium ionization layer across the solar cycle. In K. Fletcher (Ed.), Proceedings of SOHO 18/ GONG 2006/ HELAS I: Beyond the spherical Sun. Noordwijk, The Netherlands: ESA Publications Division.