This document discusses several models of knowledge management that have been developed and applied in organizations. It describes the Von Krogh and Roos model, which differentiates between individual and social knowledge and sees knowledge as a system influenced by people's thinking and external environment. It also outlines the Nonaka-Takeuchi model of knowledge creation starting at the individual level and being converted into organizational knowledge. Additionally, it summarizes Choo's model of how organizations select and use information from the external environment, and Wiig's model focusing on organizing useful knowledge sources. Boisot's model views knowledge as derived from data through an observer's experience and considers knowledge diffusion between an observer and receiver.