9982 Lars Hedin/Gene Likens: Atmospha''rischer Staub und saurer Regen.
Spektrum 1997/4, 52-55.

14205 Kevin Krajick: Long-term data show lingering effects from acid
rain. Science 13 April 2001, 195-196.

7837 G. Likens/C. Driscoll/D. Buso: Long-term effects of acid rain: response
and recovery of a forest ecosystem. Science 12 April 1996, 244-246.