- http://www.unece.org/env/lrtap/protocol/94sulp_a/annex4.htm This page contains a list of major sources of sulfur emissions and possible ways to clean up and reduce emission levels.
- http://www.environmentaldefense.org/pubs/EDF-Letter/1983/Aug/e_nyacidrain.html This is a newsletter stating that the EDF Urges N.Y. State to control in-state acid rain sources, and was printed in 1983. It sites several local sources of acid rain, and possible mitigation.
- http://www.att.virtualclassroom.org/vc98/vc_63/iwai/rain.html This is a virtual classroom page on the causes of acid rain. It describes sources of sulfoxides and what the chemical reaction.
- http://www.chinadaily.com.cn/cndy/history/1999/05/d2-2bac.e04.html This is a report by the China Daily on the major source of sulfur dioxide, coal. It describes the history of emissions for approximately the last 20 years.