What is the rationale for having references before the article text?
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.