Here's One - "In the summer of 2007, former National Basketball Association (NBA) referee Tim Donaghy was found to have bet on games that he officiated."
Here's another link
Researchers' NBA officiating study detects biases, but not necessarily the ones fans suspect | OregonLive.com
"But the same study found that NBA referees tend to favor home teams, teams trailing in a game and teams trailing in a playoff series"
"Still, the study concludes that the detected referee biases, though probably unintentional, could increase the league's revenues through additional ticket sales and television appearances by reducing the number of blowout games and making televised games more compelling. "
And there are many more stories out there. In fact, during the playoffs watch the line from Vegas before the referees are announced and then after they are announced.
It doesn't have to be fouls called, it can be fouls not called, violations called and not called.
And according to the NY Times a study from the University of Pennsylvania stated that from 1991 to 2004 - white refs called a higher percentage of fouls against black players than against white players and that black refs called a higher percentage of fouls against white players than black (although not as great)
Now of course Stern and the NBA immediately call every study into question and challenge the credibility and so a lot of folks buy into the NBA line.
I've watched enough games over the past 30 years to know that league favorites very, very rarely foul out and unless it's obvious they can get away with murder.