Liver and muscle esterases as biomarkers of exposure to organophosphate pesticides on yellow-legged gull Larus michahellis (Naumann, 1840) from the Northwest coast of Spain. (16th September 2016) - Martinez Morcillo, S.; Fidalgo, L.; Lopez Beceiro, A.; Míguez, M.; Soler, F.; Perez Lopez, M.