Dr. Kai Engelhardt
|Tel.:||+49 9131 5 33 52 45|
|Fax:||+49 9131 5 33 52 47|
|optical design services||S||Knight Optical, NIL Technology, Oplitec, Optikexpertisen, Shanghai Optics|
Column "To": S = list of suppliers for that product, E = encyclopedia article.
Third column: alternative suppliers are suppliers also offering such products while having an ad package. On their own company profile pages, the right column of the table contains their product descriptions instead of alternative suppliers.