1. The weathering of phosphate deposits — geochemical and environmental aspects;Altschuler,1973
2. Phosphorites on the Sea Floor, Origin, Composition and Distribution;Baturin,1982
3. Thermal Analysis;Blazek,1972
4. U-series, oceanographic and sedimentary evidence in support of recent formation of phosphate nodules of Peru;Burnett;Soc. Econ. Paleontol. Mineral., Spec. Publ.,1980
5. Chemical weathering of the economic phosphates of Abu Tartur, Western Desert, Egypt;El-Kammar;Chem. Geol.,1983