“Lyell and Owen on Development“. Charles Lyell and Herbert Spencer, 1851.
“The Development Hypothesis“. Herbert Spencer, 1852.
“Progress: Its Law and Cause“. Herbert Spencer, 1857.
“Owen on the Homologies of the Vertebrate Skeleton“. Herbert Spencer, 1858.
“Illogical Geology“. Herbert Spencer, 1859.
Principles of Psychology. Herbert Spencer, 1855.