You are reading a journal of a professional genealogy organization. There are many citations throughout the articles. How did the authors know how to create the citations?
There is more than one way to write a citation. However, the book that is used by many professional genealogists is Evidence Explained by Elizabeth Shown Mills. The book not only guides one on how to write a citation. The book also explains the different types of evidence and the different types of sources. And, the book explains so much more!
I recommend that you examine the book. I do not research without it!