W., J., D., T., J., R.(1975).Learning together and alone : cooperation, competition, and individualization / David W. Johnson, Roger T. Johnson .New Jersey:Prentice-Hall.
Gaya MLA
Johnson, David, W.., Johnson, Roger, T.."Learning together and alone : cooperation, competition, and individualization / David W. Johnson, Roger T. Johnson".New Jersey:Prentice-Hall,1975.Textbook.