Why is the commentator suggesting that when we read materials in Bix, pay particular attention to the references to three key economic theories that address the impact of economics on justice: (1) the perennial analysis; which goes to the issue of the existence of external costs; (2) the Kaldor-Hicks approach; which addresses primarily for court analysis whether external costs could have been paid by a party made better off by the transaction, leaving that party still better off; the complexity there is under the Kaldor-Hicks analysis; it's not essential that the court actually transfer the transactional cost to one of the parties, it's just the fact that they could have that inserted and the leading transaction party is still better off now; and (3) perhaps the most influential in the development of economic thought in the earliest 20th century is Ronald Coase, author of the Coase Theorum