Styrofoam as beverage container?

Styrofoam is used in many countries as container for serving beverages. In the country I live in styrofoam cups are extensively used for serving hot beverages. I read that there is styrene migration from the cup to the beverage which grows in relation to the nature of food. Can anyone point to me some data which proves this statement. What I am looking for is a research paper or university communication or a health agency statement. I mean not any other website which gives out opinions.