@article{LeuL:06a,
  journal = {Electronic Notes in Theoretical Computer Science},
  volume = 165,
  title = {Proof mining in ${\mathbb R}$-trees and hyperbolic spaces },
  author = {Leu\c stean, Lauren\c tiu},
  year = 2006,
  pages = {321-335},
  note = {in Proceedings of the 13th Workshop on Logic, Language, Information
          and Computation (WoLLIC'2006), Stanford, CA, USA, July 18-21, 2006},
}