Sourcing method to facilitate vendor selection. Auctions can take several forms and can be buyer-initiated (one buyer seeking bids from multiple sellers), seller-initiated (one seller seeking bids from many buyers), or two-way (many buyers and many sellers whose bidding interactions determine the market price). (See also English Auction, Forward Auction, Dutch Auction, Vickery Auction, Reverse Auction, Yankee Auction.), (Request for Quotation) - Publication of a request for pricing quote(s) specifications related to a required product, by a prospective purchaser.