Hi dear,It is well known many job are take oversea(out of USA),also some of them back to the states(USA), for me it is a phenomenon happen no only in development countries but all around the world, no always the low income countries get jobs and righter income lost jobs. In that particular case honestly, i do not have any paper about it , but will be great if you take look USA ,Germany and India in that matter.
This is OECD policy paper. It does not treat the "call center" question specifically, but i believe this kind of analysis will be the base of your research.
Technical Report Global Value Chains and Trade in Value-Added: An Initial Ass...