Read Prof. Linder's Introduction to Takings Clause (link);Casebook p. 791-807 (Public Use Requirement)
U.S. v. Causby (casebook p. 730-738); Casebook p. 807-810 (Physical Takings and Loretto);Cedar Point decision
Regulatory Takings: Mahon (casebook p. 811-816); Penn Central (casebook p. 820-836)
If time permits: Euclid (casebook p.753-763); First English (casebook p. 816-820); Keystone, 480 US 470 (1987) (read it on Hein or WestLaw)