Puerto Rico Constitution
Article II - Bill of Rights
Section 16.

Section 16. The right of every employee to choose his occupation freely and to resign therefrom is recognized, as is his right to equal pay for equal work, to a reasonable minimum salary, to protection against risks to his health or person in his work or employment, and to an ordinary-workday which shall not exceed eight hours. An employee may work in excess of this daily limit only if he is paid extra compensation as provided by law, at a rate never less than one and one-half times the regular rate at which he is employed.