To find retail associations you can do a Google search for retail trade associations united states. I found this one http://www.rila.org/Pages/default.aspx
To find ethics violations you can also do a Google search for news articles documenting cases. I searched for retail "ethics violations" "united states" http://www.sfgate.com/business/investopedia/article/5-Most-Publicized-Ethics-Violations-by-CEOs-4235352.php this is a news article I found talking about CEO's and major ethics violations. If you want something on a smaller scale then change your keywords a bit to reflect that. I added Walmart to my search and found this http://www.nytimes.com/2007/03/29/business/worldbusiness/29iht-web-0329walmart.5068724.html?pagewanted=all&_r=0