The paper is by Boubtane, Coulibaly, & Rault (October 2012). It is titled "Immigration, Growth and Unemployment: Panel VAR Evidence from OECD Countries." From the conclusions:
In order to tackle the problem of aging populations, immigration may be considered as a potential solution to compensate for labour shortage in many OECD countries. Our results indicate that immigration flows, do not harm the employment prospects of residents, native- or foreign-born. Hence, OECD countries may adjust immigration policies to labour market needs, and can receive more migrants, without worrying about a potential negative impact on growth and employment.
Now it is more difficult to attract immigrants because of more economic opportunities available in developing countries, a long way to go regarding the quality of institutions in these countries, however.