Assorted links by Tyler Cowen December 18, 2013 at 1:01 pm in 1. What is scarce. 2. The dangers of barter with gingerbread biscuit tickets. And Izabella Kaminska on shadow banking as free banking. 3. Clemens reviews Collier on immigration. 4. Will drones revolutionize agriculture? 5. A chat with Geoffrey Hill. 6. Pre-order the new Murakami book here, due out in August. 7. More excellent John Cochrane on the Nobel Laureates and finance. And behavioral economics at the movies.