The document discusses three different expert perspectives on the stages of group development, highlighting the key stages identified by each. Corey's five stages include pre-group, initial, transition, working, and final stages, focusing on the group's formation, member experiences, and the final integration of learning. Jacobs et al. and Southern et al. propose fewer stages but emphasize the importance of member interaction, trust-building, and the leader's role in facilitating progress throughout the group process.