The first section of a scientific paper $($after the abstract$)$ is the Introduction. This is where the researchers provide relevant background information on their topic of investigation. This section shows that the researchers have read and are familiar with the research that has already occurred on this topic. It is full of footnotes or in$-$text citations $($this article uses in$-$text citations$)$ that inform the reader about the origin of the information $($i$.$e$.$ where that information came from$).$ This allows the reader to look up the original research, if they so desire.

Read the first paragraph of the Introduction carefully. This is where some of the most important background information is often found. Notice the number of in$-$text citations these authors used to provide evidence for their statements about students' use of laptops in classes. How many unique $($i$.$e don't count repeats of the same citation$)$ citations are there in the first paragraph of this article? Write the number in the blank below.