Range of Hands to Play With 3-4 People, Heads Up

[Kuberr]

I know that I need to be more aggressive when there are only 3-4 people left and even more so when playing heads up, but I don't know what hands I should be playing and what range. I understand that something like K7os is pretty good heads up, but how good?

Can anyone explain or link me to an article that does so?