The mission as a frontier institution in the Spanish american colonies, by Herbert E. Bolton.

http://www.archive.org/details/missionasfrontie00boltrich

In the Ojibway country : a story of early missions on the Minnesota frontier

http://www.archive.org/details/inojibwaycountry00scheiala

The call of the waters; a study of the frontier, by Katharine R. Crowell ...

http://www.archive.org/details/callofwatersstud01crowrich