The World: Sailing Ship Routes
<bdi><a href="https://en.wikipedia.org/wiki/en:United_Kingdom_Hydrographic_Office" class="extiw" title="w:en:United Kingdom Hydrographic Office"><span title="UK government agency concerned with providing hydrographic and marine geospatial data">United Kingdom Hydrographic Office</span></a>
</bdi>
<i>Ocean Passages for the World</i> compiled by Boyle T. Somerville. Second Edition revised by A.F.B. Woodhouse. London: Hydrographic Department of the Admiralty, 1950.