APA

Harris Helm J., Katz L. G., .Young investigators: the project approach in the early years. United States of America: Teachers college : Columbia University: .

Chicago

Harris Helm Judy, Katz Lilian G, .Young investigators: the project approach in the early years. United States of America: Teachers college : Columbia University: .

Harvard

Harris Helm J., Katz L. G., .Young investigators: the project approach in the early years. United States of America: Teachers college : Columbia University: .

MLA

Harris Helm Judy, Katz Lilian G, .United States of America: Teachers college : Columbia University: . .