Dioxin Mass Balance for the City of Hamburg, Germany. Part 4: Follow up Study – Trends of PCDD/PCDF Fluxes Publication Attachment: 96-97.pdf Authors: Friesel, P, Sievers, S, Fiedler, H, Gras, B, Lau, C, Reich, T, Rippen, G, Schacht, U, Vahrenholt, F Year: 1996