Same author, same year, how do I control the order the articles appear in (i.e.. which is assigned which letter a, b, c) ?

Hi, I have 3 articles I’d like to cite they are all by the same first author in the same year:

i.e. Smith et al (2010a), Smith et al (2010b), Smith et al (2010c)

I would like a, b, and c to be assigned based on either 1. the order in which the articles were published, or 2. the order they appear in the text, however they currently appear in the wrong order.

***** FIXED *****

I have just corrected this problem before submitting my query. a, b, and c were being assigned based on the order in which I imported the citations into endnote. I deleted the records and reimported them in the correct order and the problem was solved. I am still posting as I thought this might be useful to others at some point.