The north sea region in the early medieval period. 400 - 950

MLA

Van Regteren Altena, H. H, and H. A Heidinga. The North Sea Region In the Early Medieval Period. 400 - 950. Amsterdam, 1977.

APA

Van Regteren Altena, H. H, & Heidinga, H. A. (1977). The north sea region in the early medieval period. 400 - 950. Amsterdam.

Chicago

Van Regteren Altena, H. H., and H. A Heidinga. The North Sea Region In the Early Medieval Period. 400 - 950. Amsterdam, 1977.