It does not appear that I am able to link to their articles from the web site.
I was surprised that the studies did not result in better performances across the board. After giving it a second thought, I should say that I think a program of two-a-days would work well for me. I have a hard time putting in a workout first thing in the morning. I think a short run to loosen up in the morning would be beneficial to the afternoon workout. Also, if the time windows are available throughout the day, I don't think it could hurt to squeeze in a low impact run. As this forum has revealed many times, different things work for everyone.
Sorry about not providing the article. Marathon and Beyond is one of the better running periodicals I have read, up there with Running Times in my opinion.