Chluba, J. High Energy Astrophysics, MPI for Astrophysics, Max Planck Society;
Sunyaev, R. A. High Energy Astrophysics, MPI for Astrophysics, Max Planck Society;
Rubino-Martín, J. A., Chluba, J., & Sunyaev, R. A. (2008). Lines in the cosmic microwave background spectrum from the epoch of cosmological helium recombination. Astronomy & Astrophysics, 485(2), 377-393. doi:10.1051/0004-6361:20078993.