Tertiary Sources Tertiary sources are publications that summarize and digest the information in primary and secondary sources to provide background on a topic, idea, or event. Encyclopedias and biographical dictionaries are prime examples of tertiary sources.
From Wikipedia, the free encyclopedia. A value-added service (VAS) is a popular telecommunications industry term for non-core services, or in short, all services beyond standard voice calls and fax transmissions. However, it can be used in any service industry, for services available at little or no cost, to promote their primary business.
SRS stands for supplemental restraint system. Airbags are supplemental restraints because they help another system, or they are secondary to another system, in this case the seat belts. Airbags are not meant to be used without a seat belt; in fact they can be very dangerous or even deadly without using your seat belt.