Before getting to the papers here is a description of the event and this was the live update page. To try to minimize the effect of luck the AI played against 4 pros with two sets of mirrored hands. So for instance if the AI had AA vs KK against one pro it would have KK vs AA against the other pro. All-ins were also equity chopped. So if the AI went all-in with a 10% chance of winning it would immediately receive 10% of the pot and the pro would receive 90% - similar to the result that would happen if you ran the scenario hundreds of times.
In no limit poker players generally play with 100 bets. So at table where the minimum bet is $1 players would buy in for $100. Deeper stack play is more complex and gives good players a generally bigger advantage, and vice versa for smaller stack play. In this event the minimum bet was $100 and they played with stacks of 200 bets each hand, or $20,000.
Each night the players would receive the hand histories all hands and were able to discuss and formulate ideas and strategies with each other. The bot itself also learned from the hands it played each night, but did not adjust while playing during each day's hands.
After playing 120,000 hands, the AI was up $1,766,250 in total against the 4 pros. It was also up individually against every single pro. The smallest amount it was up was $85,649 against one player who's run of cards was incredibly lucky. The mirrored version of this matchup, where the AI received that run of lucky cards, had the AI up $880,087. In the other matchup where the run of cards was more balanced for both sides the AI was up $522,857 against one pro and $277,657 against the other.
Onto the papers:
This is the most recent and relevant: Safe and Nested Endgame Solving in Imperfect-Information Games.
Here is a link to the lead researcher's homepage with links to more papers and other academic information related to this: http://www.cs.cmu.edu/~noamb/research.html
The pros and researchers also did an AMA on Reddit here. The gist is that the players think the AI is already likely completely unbeatable for humans, though of course far from perfect. The pros tried a wide array of different ideas and strategies against the bot - nothing worked. The bot itself is capable of assessing the players' play on each hand and indicating when it thinks somebody is making a mistake. Would be a hugely cool tool to play around with. It will also probably destroy online poker in the longrun. There are already bots that do well online, but nothing like this.
Finally, this is the first incomplete information game AIs have 'conquered' excepting perhaps the stock market. The Google AI that stomped the world champion in Go is now taking on Starcraft 2 so we should expect to see some more really intriguing accomplishments from AI in the near future.