External sources
Are the sources that are outside the company.
Examples of external sources may be Internet (web pages from government agencies, competing web pages, etc..), Government offices, local competitors, suppliers, distributors, customers, newspapers, magazines, etc., Where You can obtain information regarding statistics, trends, preferences, etc.
Also, sources of information also can be classified into primary and secondary sources:
Primary Sources
Are the sources that provide information or data “first hand”, ie information obtained directly by the company.
Primary sources, generally are more expensive than the secondary sources should be used when there are no secondary sources, or when the latter providing information is insufficient or inadequate.
Examples of primary sources can be the people surveyed, interviewed or surveyed for market research, company staff, sales records, sales staff, etc.
Secondary sources
Are the sources that provide information or data that have already been published or collected for purposes other than today.
Secondary sources usually are inexpensive and are obtained quickly, so one must look first before the primary sources.
Examples of secondary sources can be the foundation for enterprise data, database, shopping, government, associations, chambers of commerce, statistical institutes, universities, research centers, trade shows, libraries, books, newspapers, magazines, etc.