<em> The words also, however, instead, and therefore are examples of </em><em>transitional expressions.</em>
Explanation:
<em>Transitional expressions</em><em>, transitional words</em> or just <em>transitions </em>are words or phrases that show how one sentence is related to the preceding one. This helps the reader follow the writer's line of thought and the text's cohesion. There are many types of transitional expressions, such as addition (<em>also</em>,) opposition (<em>however, instead</em>,) cause and effect (<em>therefore</em>,) time, sequence, etc.
It is the only one that tells the person the author, the publishing date, etc. I don't really think the other ones tell the person how to find the source.
