There is an agreement in writing between the issuer and the user, including labor, that labor. Environment for human rights work. User rights and obligations of each party.
There was an agreement in writing between the workers and laborers. These include labor. Environment, human rights, labor rights and obligations of each party.
An agreement with written between the exert work and labor, which includes the use of force, human rights, environmental work. The workers' rights and obligations of each party.