Novel kinematic methods to trace Spiral Arms nature using Gaia data S. Roca-Fàbrega, F. Figueras, O. Valenzuela, M. Romero-Gómez, T. Antoja, P. Colín, B. Pichardo and H. Velázquez EAS Publications Series, 67-68 (2014) 393-394 Published online: 17 July 2015 DOI: 10.1051/eas/1567083