Ref.: Halkoaho, T.A.A., Alapaieti, T.T., and Lahtinen, J.J. (1989a) The Sompujärvi PGE mineralization in the Penikat layered intrusion, Northern Finland. In Early Proterozoic layered intrusions in the northeastern part of the Fennoscandian Shield (T. Alapieti, Editor). Fifth International Platinum Symposium, Guide to the Post-Symposium Field Trip, Geol. Survey of Finland, Guide 29: 71-92.
Halkoaho, T.A.A., Alapaieti, T.T., and Lahtinen, J.J. (1989b) The Sompujärvi PGE mineralization in the Kirakkajuppura area. Descriptions of Post-Symposium Field Excursion Sites. Site 6. In Early Proterozoic Layered Intrusions in the Northeastern Part of the Fennoscandian Shield (T Alapieti, Editor). Fifth International Platinum Symposium, Guide to the Post-Smposium Field Trip, Geol. Survey of Finland, Guide 29: 212-216.
Halkoaho, T.A.A., Alapaieti, T.T., and Lahtinen, J.J. (1990) The Sompujärvi PGE Reef in the Penikat layered intrusion, northern Finland. Mineralogy and Petrology: 42: 39-55.
Halkoaho, T.A.A. (1993) The Sompujärvi and Ala-Penikka PGE reefs in the Penikat layered intrusion, northern Finland: implications for PGE reef-forming processes. Acta Univ. Oul. A249, University of Oulu, Oulu, Finland.
http://www.gsf.fi/explor/pgeweb/penikat/sompuj_pge_reef.htm
PGE deposit in the Penikat ultramafic complex.
