Now here is the situation. I've had a couple clients I've worked for that they are no longer with me due to them moving in other directions beyond SEO. The last client was a pain to deal with and they cancelled their service with us complaining not enough was been done for them (although we got them plenty of leads, but their conversion sucked) and they complained all the time. Another client was a friend of mine that used our service for about a year, we got them ranking for his keywords on the front page, but it seem like it wasn't converting as well for them so they decided to put SEO on the back burner and try other things.
Right now I'm working on a web design/SEO for my sister-in-law for her new business so that one is currently active. We also did a web design for this other company only (no SEO) and they were satisfied with their end product.
So should I have them try to contact my friend and sister-in-law for references or should I try to do in it in another way about we don't like to disclose any client information and see what they say?