'I've had unsafe sex so many times why bother being safe now?': the role of cognitions in sexual risk among American Indian/Alaska Native men who have sex with men. - Nelson KM; Simoni JM; Pearson CR; Walters KL; Nelson, Kimberly M; Simoni, Jane M; Pearson, Cynthia R; Walters, Karina L (Annals of Behavioral Medicine, 2011)