86-km optical link with a resolution of 2 × 10-18 for RF frequency transfer O. Lopez, A. Amy-Klein, C. Daussy, C. Chardonnet, F. Narbonneau, M. Lours and G. Santarelli Eur. Phys. J. D, 48 1 (2008) 35-41 Published online: 04 April 2008 DOI: 10.1140/epjd/e2008-00059-5