The effect of intergalactic helium on hydrogen reionization: implications for the sources of ionizing photons at z>6B. Ciardi(Max Planck Institute for Astrophysics), Luca Graziani(Astronomical Observatory of Rome)Monthly Notices of the Royal Astronomical SocietyApril 23, 201210.1111/j.1365-2966.2012.20902.xCited by 57SaveCiteExport RISWatch citationsRelated PapersA large light-mass component of cosmic rays at 1017–1017.5 electronvolts from radio observations|Nature|2016|155