A large amount of research has been conducted on this topic (see Judd and Scadding [1982], Laidler [1985], and Goldfeld and Sichel [1990] for extensive surveys).

• 关于这方面的研究可参见Judd和Scadding（1982），Laidler (1985), 以及 Goldfeld 和 Sichel（1990）。