Stock, James H., and Mark W. Watson. Introduction to Econometrics. Fourth edition. Harlow, United Kingdom: Pearson Education Limited, 2020. Web. <https://bibliu.com/users/saml/samlUCL?RelayState=eyJjdXN0b21fbGF1bmNoX3VybCI6IiMvdmlldy9ib29rcy85NzgxMjkyMjY0NTIzL3BkZjJodG1sZXgvaW5kZXguaHRtbCJ9>.