Try this book if you don't know where to start your research or if you don't quite understand what you're looking for. Chapters cover how to find company and industry information, common business acronyms, lists of government agencies, an introduction to stocks and mutual funds, and many other basic topics.
Business writing isn't the same as writing a history paper or biology lab report. This book covers all kinds of business writing from resumes and resignation letters to taking meeting minutes and giving business presentations.
Focusing primarily on North American business, this encyclopedia provides an efficient way to read more about business concepts that may be new to you.
Need some introductory info?
Youtube Video - How to Get Started with Online Encyclopedias
The Business Reference and Services Section (BRASS) of the American Library Association has put together several guides filled with great resources for a range of business topics
BEOnline Plus is the Library of Congress's catalog of business/economics resources. Access is by title or subject lists, including categories like accounting, business plans, finance, international development, industries, and companies.
This World Bank site provides free access to publications that help businesspeople worldwide conduct business in a wide variety of countries. Considered an essential resource to business schools, this site provides free access to many reports.
"Export.gov brings together resources from across the U.S. Government to assist American businesses in planning their international sales strategies and succeed in today’s global marketplace." Offers quite a bit of data by industry and country.
"Offers a rich collection of thousands of international business- and trade-related resources, which [have been] selected for their content and usability and organized into the categories below to facilitate your research."
ThomasNet is an industrial search engine that is "designed for sourcing components, equipment, MRO products, raw materials and custom manufacturing services."
Strauss's Handbook of Business Information by 
The AMA Handbook of Business Writing by 
Encyclopedia of Business by 
Hekman
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