D. G. Pike, T. Gunnlaugsson, G. Desportes, B. Mikkelsen, G. Víkingsson, and D. Bloch, “Estimates of the Relative Abundance of Long-finned Pilot Whales (Globicephala melas) in the Northeast Atlantic from 1987 to 2015 indicate no long-term trends”, NAMMCOSP, vol. 11, Feb. 2019.