@article{Valles:77126,
      author        = "Valles, J.A. and Martin, J.C. and Berdejo, V. and Cases,
                       R. and Alvarez, J.M. and Rebolledo, M.A.",
      title         = "{Assessment of effect of Yb3+ ion pairs on a highly
                       Yb-doped double-clad fibre laser}",
      year          = "2018",
}