When looking for references in a bibliography, it is much easier when you know what kind of publication it is.
Habermas, J., & Habermas, J. The future of human nature. Cambridge: Polity, 2003.
Chapter in an edited book
Feinberg, J. "The Child's Right to an Open Future." Whose child?: Children's rights, parental authority, and state power. Ed. W.Aiken and H. LaFollette. Totowa, NJ: Littlefield, 1980. 124-53.
Greer Donley, Sara Chandros Hull, and Benjamin E. Berkman, "Prenatal Whole Genome Sequencing: Just Because We Can, Should We?" Hastings Center Report 42, no. 4 (2012): 28-40. DOI: 10.1002/hast.50
Researchers can often find useful scholarship by identifying one particularly relevant book or article and seeing which sources that text cites. With print texts, this process might involve checking the bibliography. In some databases, you can also trace citations forward in time and find subsequent material that cites a particularly useful resource. Use the following databases to find a relevant resource and then see which later texts cite the one with which you start. Keep in mind, however, that the citations will no be comprehensive—i.e., the citations will often be limited by the scope of the database in which you're working.