[Tex/LaTex] Lyx citation style: et al only when three or more authors

Question

I'm using lyx and bibtex for my master thesis. In lyx, I changed the bibliography style from standard to natbib (author-year). The problem occurs when I cite a paper with two authors. The reference to the paper is then like "Kahneman et al. (1979)" instead of "Kahnemann & Tversky (1979)". According to Harvard citation style, "et.al." should be used when three or more authors, not for two. Is there a way to change this?

Answer 1

A well-known bibliography style that generates authoryear-style citation call-outs and uses & as the conjunction if the bib entry has exactly two authors (or editors) is agsm. This bibliography style is part of the harvard citation management package, but it's compatible with the natbib package as well.