it's really nice that some long out of print books are in the public domain and are now online available to download.

Bullen's Songs of Sea Labor

https://ia902800.us.archive.org/28/items/songsofsealabour1914bull/songsofsealabour1914bull.pdf

RR Terry's Shanty Book I & II

https://urresearch.rochester.edu/institutionalPublicationPublicView.action?institutionalItemId=24944&versionNumber=1