1. Microbial Ecology;Alexander,1971
2. The pre-3760 Myr old supracrustal rocks of the Isua area, central West Greenland and the associated occurrence of quartz banded ironstone;Allaart,1976
3. Aeolian differentiation of basaltic tuffs in the Early Precambrian Isua supracrustal belt West Greenland;Appel;Neues Jahrb. Mineral Mh. 1977,1977
4. Appel (to be published) Stratabound copper sulfides in a banded iron-formation and in basaltic tuffs in the Early Precambrian Isua supracrustal belt, West Greenland. To be published in Econ. Geol..
5. Least radiogenic terrestrial lead from Isua, West Greenland;Appel;Nature,1978