@Article{ 
  frakov11,
  author = { Frank, Rupert and Kovarik, Hynek },
  title = { Heat kernels of metric trees and applications },
  journal = { SIAM J. MATH. ANAL. },
  year = { 2013 },
  doi = { 10.1137/120886297 },
  volume = { 45 },
  pages = { 20 },
  URL = { http://cvgmt.sns.it/paper/134/ },
  note = { cvgmt preprint}
}