@Article{KMU15,
  author     =  {{K}\"uhn, Thomas and {M}ayer, Sebastian and {U}llrich, Tino},
  title      = {{C}ounting via entropy: new preasymptotics for the approximation numbers of {S}obolev embeddings },
  year       = {2016},
  volume = {54(6)},
  pages = {3625 -- 3647},
  journal    = {SIAM Journ. on Numerical Analysis},
  annote     = {journal,group},
  eprint     = {1505.00631},
  pdf        = {http://ullrich.ins.uni-bonn.de/KMU15.pdf}
}