Apatite in early Archean Isua supracrustal rocks, southern West Greenland : its origin, association with graphite and potential as a biomarkerLepland, Aivo; Arrhenius, Gustaf; Cornell, DavidPrecambrian research2002 / p. 221-241 : ill https://doi.org/10.1016/S0301-9268(02)00106-7