MLA
Crowther, Samuel, 1806?-1891. The gospel on the banks of the Niger : journals and notices of the native missionaries accompanying the Niger Expedition of 1857-1859. 1968. Samuel Ajayi Crowther and Western African Christianity in the Nineteenth Century. Pitts Theology Library. https://digital.library.emory.edu/purl/0687h44kgk-cor.
APA, 6th edition
Crowther, Samuel, 1806?-1891. (1968)[The gospel on the banks of the Niger : journals and notices of the native missionaries accompanying the Niger Expedition of 1857-1859, [1st edition] reprinted.]. Samuel Ajayi Crowther and Western African Christianity in the Nineteenth Century, Pitts Theology Library. https://digital.library.emory.edu/purl/0687h44kgk-cor.
Chicago
Crowther, Samuel, 1806?-1891, The gospel on the banks of the Niger : journals and notices of the native missionaries accompanying the Niger Expedition of 1857-1859, 1968, Samuel Ajayi Crowther and Western African Christianity in the Nineteenth Century, Pitts Theology Library. https://digital.library.emory.edu/purl/0687h44kgk-cor.