1. Lysons, K., & Farrington, B. (2020). Procurement and Supply Chain Management (10th ed.). Pearson. In Chapter 11, "E-procurement," the text explains that e-sourcing tools provide buyers with access to a wider range of suppliers, increasing competition and price transparency. This process inherently enhances the buyer's bargaining power by reducing the supplier's leverage (Section 11.4, pp. 328-330).
2. Cagliano, R., Caniato, F., & Spina, G. (2003). E-business strategy: how companies are shaping their supply chain through the internet. International Journal of Operations & Production Management, 23(10), 1142-1162. The study notes that the internet reduces buyers' search costs and increases the availability of information about alternative suppliers. This "increases the competitive pressure on suppliers and shifts the bargaining power from the supplier to the buyer" (p. 1146). DOI: https://doi.org/10.1108/01443570310496607
3. Van Weele, A. J. (2018). Purchasing and Supply Chain Management (7th ed.). Cengage Learning. Chapter 14 discusses e-procurement solutions, highlighting how systems like electronic marketplaces and reverse auctions empower buyers. These technologies "increase the level of competition between suppliers... As a result of increased transparency in the market, the buyer’s negotiating position is strengthened" (p. 421).