Proposals The CREMA Proposal on laser spectroscopy in muonic helium. CREMA collaboration linksMuonic hydrogen webpage, LKB ParisMuonic hydrogen webpage, MPQ MunichHydrogen spectroscopy, MPQ MunichPrecision physics at low energy, ETH Zurich Codata ValuesHydrogen Energy Levels (NIST)Proton Radius value (NIST)Fundamental Physical Constants (NIST)