Leading marriage experts, state government officials and highly respected researchers nationwide serve as the Oklahoma Marriage Initiative Research Advisory Group. The purpose of the group is to provide professional expertise to guide research efforts and to apply findings to the development of future programs and services. The website provides links to experts nationwide.

The National Healthy Marriage Resource Center is a clearinghouse for high-quality, balanced and timely information and resources on healthy marriage. The organization’s mission is to be a first stop for information, resources and training on healthy marriage for experts, researchers, policymakers, media, marriage educators, couples and individuals, program providers and others.

The National Center for Family & Marriage Research at Bowling Green State University in Ohio supports research on the effects of family structure on family members and the wider society. Research topics supported by the center include religion and spirituality. The center’s website has links to other research centers, too.

The Coalition for Marriage, Family and Couples Education is dedicated to making marriage education widely available. Diane Sollee is director.

Child Trends is a nonprofit, nonpartisan research center dedicated to improving children’s lives. One focus of its studies is marriage and family.

The American Association for Marriage and Family Therapy is the professional association for the field of marriage and family therapy. The organization represents the professional interests of more than 50,000 marriage and family therapists throughout the United States, Canada and abroad.

Unmarried Equality (originally the Alternatives to Marriage Project) is a nonprofit organization that advocates for equality and fairness for unmarried people. The organization, which is based in Brooklyn, N.Y., says it does not oppose marriage but wants validation and support, including nondiscriminatory public policies, for those who are single or in nonmarital relationships.

The U.S. Census Bureau provides a summary page on marital status and living arrangements.

Psychology Today offers a summary page on marriage, including articles and blogs by relationship experts. The page also includes links to pages on related topics, including divorce, homosexuality and relationships.