Everything looks correct to me.
One thing - clicking the cite link gets me this:
Pierce, Rod. "Line in Geometry" Math Is Fun. Ed. Rod
Pierce. 12 Sep 2007. 12 Sep 2007
Maybe I'm just not used to citing things, but it seems very repititious.
Why did the vector cross the road?
It wanted to be normal.
Roughly: Author, Title, Publisher, Editor, Published, Accessed, <URL>
"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman