Second law of thermodynamics
The second law of thermodynamics may be expressed in many specific ways, the most prominent classical statements being the statement by Rudolf Clausius (1854), the statement by Lord Kelvin (1851), and the statement in axiomatic thermodynamics by Constantin Carathéodory (1909). These statements cast the law in general physical terms citing the impossibility of certain processes. The Clausius and the Kelvin statements have been shown to be equivalent.
Josiah Willard Gibbs
The first half of the 20th century saw the publication of two influential textbooks that soon came to be regarded as founding documents of chemical thermodynamics, both of which used and extended Gibbs's work in that field: these were "Thermodynamics and the Free Energy of Chemical Processes" (1923), by Gilbert N. Lewis and Merle Randall, and "Modern Thermodynamics by the Methods of Willard Gibbs" (1933), by Edward A. Guggenheim.