Mumpower, Jeryl L., and Stuart W Cook. 1978. “The Development of Interpersonal Attraction in Cooperating Interracial Groups: The Effects of Success-Failure, Race and Competence of Groupmates, and Helping a Less Competent Groupmate”. International Journal of Group Tensions 8: 18-50. Referenced from psycnet.apa.org: The development of interpersonal attraction in cooperating interracial groups: The effects of success-failure, race and competence of groupmates, and helping a less competent groupmate. Reference Link
Blanchard, Fletcher A, Leonard Adelman, and Stuart W Cook. 1975. “Effect of Group Success and Failure Upon Interpersonal Attraction in Cooperating Interracial Groups”. Journal of Personality & Social Psychology 31: 1020-30. doi:10.1037/h0076953. Reference Link
Blanchard, Fletcher A, Russell H. Weigel, and Stuart W Cook. 1975. “The Effect of Relative Competence of Group Members Upon Interpersonal Attraction in Cooperating Interracial Groups”. Journal of Personality & Social Psychology 32: 519-30. doi:10.1037/h0077084. Reference Link
Blanchard, Fletcher A, and Stuart W Cook. 1976. “Effects of Helping a Less Competent Member of a Cooperating Interracial Group on the Development of Interpersonal Attraction”. Journal of Personality and Social Psychology 34: 1245-55. doi:10.1037/0022-3514.34.6.1245. Reference Link