I have not applied to this program but I've gone through a part-time MBA. I doubt that an online program for working professionals is as rigorous about references as, say, undergrad admission to an Ivy League program or Oxford or Hogwarts or something. Just get a couple of coworkers with a similar advanced degree to write something that says "this person exists and I think they can handle the load" and you'll be fine. Remember that college is a business; if you look like you can both handle the program and pay for it, they'll let you in.