Kreveld, D. v. (1970). Structure and outcomes of study groups: A method of determining several properties of group structure and some relationships observed with group outcomes. Van Gorcum.
Chicago-viite (17. p.)Kreveld, David van. Structure and Outcomes of Study Groups: A Method of Determining Several Properties of Group Structure and Some Relationships Observed with Group Outcomes. Assen: Van Gorcum, 1970.
MLA-viite (8. p.)Kreveld, David van. Structure and Outcomes of Study Groups: A Method of Determining Several Properties of Group Structure and Some Relationships Observed with Group Outcomes. Van Gorcum, 1970.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.