How to cite several papers at once with first same authors? I would like to cite both Potter, Granger and Weasley (1995) and Potter, Granger and Weasley (1998) for the same claim. I would write


  Hogwarts is a school of magic (Potter et al. 1995,1998).


Now let's assume I would like to cite both Potter, Granger and Weasley (1995) and Potter, Dumbledore and Snape (1997) for the same claim. Should I write


  Hogwarts is a school of magic (Potter et al. 1995,1997).


or 


  Hogwarts is a school of magic (Potter et al. 1995; Potter et al. 1997).


I doubt it vary much among journals but FYI I am aiming Molecular Ecology who uses the APA reference style as indicated in the guidelines to authors.
The APA reference guide from Purdue denotes how the articles should be listed and referred to inline. So my understanding of the two links above would be something like (using the examples they have):


  [the claim you want to use the reference] (Wegener et al. 2000; Wegener et al. 1994).


would be inline reference and in the references list it would be


  Wegener, D. T., Kerr, N. L., Fleming, M. A., &amp; Petty, R. E. (2000). Flexible corrections of juror judgments: Implications for jury instructions. Psychology, Public Policy, and Law, 6, 629-654.
  
  Wegener, D. T., Petty, R. E., &amp; Klein, D. J. (1994). Effects of mood on high elaboration attitude change: The mediating role of likelihood judgments. European Journal of Social Psychology, 24, 25-43.


On a separate note: Are you using a reference manager like papers3, mendeley or zotero? If so just insert the citekey for the articles and choose the style, let the software do the work for you. Saves you the headache..