16.1 Who are the major suppliers?
16.2 Are multiple suppliers used, or do single suppliers provide products/services?
Workers are the best source for identifying materials and suppliers. Some information may be found on the company’s SEC Form 10-K (available from the SEC’s EDGAR database), the company web site, or the company annual report. Panjiva lists the major suppliers for major firms. Thomas Register provides information on brand names.
Import Genius allows you to track containers and third part shippers (this is a fee-based database, but relatively inexpensive).