Lewis LA, Calambokidis J, Stimpert AK, ym. Context-dependent variability in blue whale acoustic behaviour. Royal Society Open Science. 2018;5(8). Available at: http://rsos.royalsocietypublishing.org/lookup/doi/10.1098/rsos.180241https://syndication.highwire.org/content/doi/10.1098/rsos.180241.