Forms and publications
Form 990 Instructions, Appendix E PDF. Group Returns – Reporting Information on Behalf of the Group (select the page link under the heading Contents for Appendix E)
Publication 4573 PDF, Group Exemptions
Web articles
Annual Electronic Notice (Form 990-N) for Small Organizations FAQs: Who Must File
Exempt Organizations Annual Reporting Requirements - Form 990, Schedule R: Group Return Reporting
Exempt Organizations Annual Reporting Requirements - Overview - Returns by Members of Group Ruling
Other materials
Report of Advisory Committee on Tax Exempt and Government Entities on Group Exemptions PDF (June 15, 2011)