TY - JOUR AU - Fabrizio Giorgetta AU - William Swann AU - Laura Sinclair AU - Esther Baumann AU - Ian Coddington AU - Nathan Newbury C2 - Nature Photonics DA - 2013-04-28 DO - https://doi.org/10.1038/nphoton.2013.69 LA - en M1 - 7 PB - Nature Photonics PY - 2013 TI - Optical two-way time and frequency transfer over free space ER -