1. Special Publication,1964
2. Special Publication,1971
3. M. MUHAMMED J. SZABON E. HÖGFELDT, Chemica Scripta, 6 (1974) 61.
4. M. AGUILAR, E. HÖGFELDT, Chemica Scripta, 2 (1972) 149.
5. E. HÖGFELDT, 2nd Dahlem Conference on Seawater, Berlin, March 10–16, 1975.