Record of lead isotopic ratios in the Torca de La Grajera ice accumulation (Cantabrian range, N Spain) - Sánchez Moreno, Lorenzo; Garralón, Antonio; Turrero, María Jesús; Ortega Martínez, Ana Isabel; Gómez González, Paloma; Martín-Merino, Miguel Ángel; Martín Chivelet, Javier (2018)