Cornell University
Cornell University: Law School: "Nonenforceability of Undertakings in Conflict"
This site, entitled "Sec. 103. - Nonenforceability of undertakings in conflict with public policy; ''yellow dog'' contracts," is from the Legal Information Institute and explains Section 103 of employer/employee jurisdiction.
Cornell University
Cornell University: Law School: Labor Law: An Overview
This site gives a description of labor law and describes government acts which protect the labor force.