http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
v. 1. 1882-1888. Early essays and Leibniz's new essays concerning the human understanding.--v. 2. 1887. Psychology.--3. 1889-1892. Early essays and Outlines of a critical theory of ethics.--4. 1893-1894. Early essays and The study of Ethics, a syllabus.--5. 1895-1898. Early essays.
Continued by: The middle works, 1899-1924.
"Result of a cooperative research project at Southern Illinois University."