George Boolos, 1998. Logic, Logic, and Logic. MIT Press. Contains several influential papers on Frege's philosophyof arithmetic and logic. Michael Dummett
on logical constants (页面存档备份,存于互联网档案馆) at the Stanford Encyclopedia ofPhilosophy; Weblog entry "How many is two?" (页面存档备份,存于互联网档案馆) by Andrej Bauer(英语:Andrej