Vanderburgh County Ozone Reduction Ordinances:
http://www.codepublishing.com/in/vanderburghcounty/html/VanderburghCounty19/VanderburghCounty19.html
City of Evansville Municipal Code – Evansville Environmental Protection Agency
http://www.codepublishing.com/IN/Evansville/html/Evansville16/Evansville1605.html
State of Indiana Air Rules
http://www.in.gov/legislative/iac/title326.html
Indiana Code Title 13. Environment
http://www.in.gov/legislative/ic/code/title13
Clean Air Act
http://www.epa.gov/air/caa//
The Plain English Guide to the Clean Air Act
http://www.epa.gov/air/caa/peg/
Code of Federal Regulations
Regulations | US EPA
Federal Register – Table of Contents
http://www.epa.gov/fedrgstr/
Regulations.gov
http://www.regulations.gov/