You can start with the Universal Declaration of Human Rights [UDHR] and go from there...
http://www.un.org/Overview/rights.html
To be specific the rights being breached in your case are:
Article 4.
No one shall be held in slavery or servitude; slavery and the slave trade shall be prohibited in all their forms.
Article 23.
(1) Everyone has the right to work, to free choice of employment, to just and favourable conditions of work and to protection against unemployment.
(2) Everyone, without any discrimination, has the right to equal pay for equal work.
(3) Everyone who works has the right to just and favourable remuneration ensuring for himself and his family an existence worthy of human dignity, and supplemented, if necessary, by other means of social protection.
(4) Everyone has the right to form and to join trade unions for the protection of his interests.
Article 24.
Everyone has the right to rest and leisure, including reasonable limitation of working hours and periodic holidays with pay.
Article 25.
(1) Everyone has the right to a standard of living adequate for the health and well-being of himself and of his family, including food, clothing, housing and medical care and necessary social services, and the right to security in the event of unemployment, sickness, disability, widowhood, old age or other lack of livelihood in circumstances beyond his control.
(2) Motherhood and childhood are entitled to special care and assistance. All children, whether born in or out of wedlock, shall enjoy the same social protection.
Then you can look into other ones such as:
The International Covenant on Civil and Political Rights
International Covenant on Economic, Social and Cultural Rights
but this should provide a start.