Reuter and MacCoun examined different ways to determine the concept of whether or not marijuana was a gateway drug. They interpreted data if there was a gateway effect and postulated if the prevention of or delayed usage of marijuana would prevent the consequential flow to use of other drugs or would limit change in the involvement sequence. Reuter P, MacCoun R. Weighing the harms of cannabis use and cannabis prohibition. In: Proceedings of the international cannabis and psychosis conference, Melbourne, Department of Human Studies, 1999.

Answer:

Reuter and MacCoun examined different ways to determine the concept of whether or not marijuana was a gateway drug. They interpreted data if there was a gateway effect and postulated if the prevention of or delayed usage of marijuana would prevent the consequential flow to use of other drugs or would limit change in the involvement sequence ( 33).

Commentary:

Again, all the information after the word "sequence" should be deferred until the Works Cited page.

If the writer had not used Reuter and MacCoun in the running text, the in-text citation should look like:

(Reuter and MacCoun 33)

Even though the writer here suggests that this material is paraphrased (because no quotation marks are used), words like "gateway effect," "postulated," "delayed usage," and "consequential flow" suggest expert terminology and not language used by the layman/student. Therefore, this author should probably opt to use quotation marks here to indicate directly quoted text.