What is the rationale for having references before the article text? Certain journals (for example, Optics Express) place the references of papers in between the abstract and the article text:



How common is this practice? Is there some specific design reason for this? As a casual reader, I find it disconcerting and annoying, and tend to see it as another barrier between googling the paper and actually getting at the text. However, I understand there may be other workflows for which this is useful. Can anyone point out possible justifications for this practice?
Usually the article consists of three or four parts. Introduction, main text which is your original research and conclusion. There may also be an appendix. 
So, usually most of the citations are from the introduction because you mainly talk about the prevosly done researches there. So, when I read the introduction I have to constantly go back and forth to check the citations, but if the citations are located nearby the introduction, it is more convenient. 

I read sceintific articles a lot and I can say that this is not a common practice in physics. I can't talk about the articles in other fields.