The APA style allows for in-text citations, direct quotations, and endnotes and footnotes. It is also enables the author to use the past tense of verbs in the reportage. Standards of the APA style include: 1  Bibliographic list of references. 2  Alphabetical order by author in the bibliographic list, then chronological by work.
Function [edit]. The pericardial fluid reduces friction within the pericardium by lubricating the epicardial surface allowing the membranes to glide over each other with each heart beat.
For cases like this, friction can be reduced using a lubricant, which is a material that reduces friction between two objects. Oil is an example of a lubricant. In other cases, friction can slow down a vehicle or a person.