Ninth Edition CoverGraziano & Raulin
Research Methods (9th edition)

Citing References in the Text

The hallmark of scientific research is that projects build on previous research and ideas. In this section, we will show you how to cite previous studies or papers in the text. In another section, we will show you how to list each of the studies or papers referenced in your paper so that a reader can find the original work that stimulated your research.

Citing a Single Work by One or More Authors

There are two standard approaches for citing a single study in the text. The first is to list the citation in parentheses after a statement based on the paper. The first example below shows this approach. The second is to list the authors in the text, with the year of publication listed in parentheses immediately after the author list.

A principle that applies throughout this section is that when an author list is incorporated into the text, the word "and" is used between the last two authors. When an author list is included in parentheses, the word "and" is replaced by the ampersand symbol (&). APA uses a serial comma in author lists, which means that there is a comma just before the ampersand or and in the list of authors.

When there are two to five authors on a single study, all authors are listed the first time the study is cited. For subsequent citations to the same study, only the first author is listed followed by the phrase "et al." If there are six or more authors, the et al. notation is used even for the first reference to the paper. If there might be confusion about what paper was being referenced, because the senior author published several papers cited in your study in the same year, you should list as many authors as necessary to make the citation unambiguous. 

Examples of each of these usages are given below.

Gottesman (1991) argued that the evidence for genetic influences in schizophrenia is overwhelming.

The evidence for genetic influences in schizophrenia is overwhelming (Gottesman, 1991).

Barlow, Hays, and Nelson (1984) argue that incorporating research methodology into clinical practice will dramatically improve both service and accountability.

Incorporating research methodology into clinical practice will dramatically improve both service and accountability (Barlow, Hays, & Nelson, 1984).

The best way to enhance accountability depends on the situation (Barlow et al., 1984).

Citing Multiple Studies

Often there is more than one study that supports a given statement, so multiple studies are cited. Typically, this is done in parentheses at the end of the sentence. 

The studies are ordered within the parentheses by the last name of the senior author and, if necessary, by the last names of junior authors. Studies are separated by semi-colons as shown below. 

Although such lists of studies occur most often at the end of a sentence, sometimes multiple lists will occur in a single sentence, with each list supporting the statement that immediately precedes it.

CAT scans and MRIs allowed researchers to look at the structure of the brain of patients with schizophrenia and compare it with the structure of brains of controls (e.g., DeLisi et al. 1997; Lewine, Gulley, Risch, Jewart, & Houpt, 1990).

PET scans (e.g., Buchsbaum, 1990; Stevens, 1997), rCBF records (e.g., Wood & Flowers, 1990), and EEGs (e.g., Gattaz et al., 1992; Josiassen, Roemer, Johnson, & Shagass, 1990) allowed researchers to look at the functioning of the brain of a patient who has schizophrenia.