Trecker and Harleigh Bradley, Social group work, principles and practices, Association Press, 1972 ISBN 978-0809618460 Joan Benjamin, Judith Bessant and Rob Watts. Making Groups Work: Rethinking Practice, Allen & Unwin, 1997 ISBN 1-86448-304-0 Ellen Sarkisian, "Working in Groups." Working in Groups - A Quick Guide for Students, Derek Bok Center, Harvard University