Limits on cosmological variation of quark masses and strong interaction
  We discuss limits on variation of $(m_q/\Lambda_{QCD})$. The results are obtained by studying $n-\alpha$-interaction during Big Bang, Oklo natural nuclear reactor data and limits on variation of the proton $g$-factor from quasar absorpion spectra. 
V.F. Dmitriev, V.V. Flambaum