In his address to a newly founded mission organization, Edmund Clowney sketched out three factors that give fuel to Reformed missions, namely, "The Glory of God", "The Grace of God", and the "Kingdom of God." His article is part of a larger collection entitled Calvin and World Mission (T. Schirmacher, ed. 2009) and it can be downloaded for free here.
Besides the warmly engaging article by Clowney, one can find articles in English and German on the history of Calvinism, its theological motivation, and even articles on matters in reaching out to one's religious neighbors next door today.
This is truly a great Christmas gift. Salvation belongs to the Lord.