123 Link
A list of every minor industry within this major industry, with some links to all of the bigger sub-industries.
http://123link.com/SICtitle/50.html

Association Central
The Web´s leading resource for locating trade associations and industry groups. Excellent site.
http://www.associationcentral.com

Briefme
BRIEFME.COM is an Internet and e-mail newsletter service which publishes over 80 FREE topical e-zines every week. 1100 contributing editors, all experts in their respective fields, scour the Web to find the best and most up-to-date information to review for the various newsletters.
http://www.briefme.com/

Business Reference Services
Business Reference Services is the starting point for conducting business research. Supported by a reference collection of over 20,000 volumes, a network of CD-ROM services, and the Adams Building Computer Catalog Center, reference specialists in specific subject assist in formulating search strategies and gaining information.
http://lcweb.loc.gov/rr/business/

Cramer Specialty Mdse. Wholesale Trade Directory
Wholesale Trade Directory contains well over 2000 Manufacturers and Suppliers, representing hundreds of thousands of products worldwide.
http://www.cramerspecialty.com/wholesale/

Edgar Online Services
Source for SEC Filings. Also available are SEC EDGAR documents going back to 1994. Service Subscriptions are available. A free Visitor´s Subscription provides many of the special features without real time access.
http://www.edgar-online.com/com/p/main.html

OK Direct
Internet business directory with nine subcategories all within this industry.
http://www.okdirect.com/Biz/5/5000.html

U.S. Census Bureau
A searchable version of the Standard Industrial Code. Very helpful.
http://www.census.gov./epcd/www/sic.html

U.S. Census Bureau Publications
Business, Trade and Services Business data covering many topics and trades -- such as sales volume at furniture stores and payrolls for toy wholesalers -- and cover small operations as well as large corporations in retail, wholesale trade, and service industries.
http://www.census.gov/prod/www/abs/business.html