"Sebastian Gagahan". A Biographical Dictionary of Sculptors in Britain, 1660–1851. Henry Moore Institute/Paul Mellon Centre. Archived from the original on 3 December 2013. Retrieved 6 February 2012.
archive.org
Smith, J.T. (1920). "Chronology". In Whitten, Wilfred (ed.). Nollekens and his Times. London: John Lane. p. xii.
"Sebastian Gagahan". A Biographical Dictionary of Sculptors in Britain, 1660–1851. Henry Moore Institute/Paul Mellon Centre. Archived from the original on 3 December 2013. Retrieved 6 February 2012.