A number of STEMMA source-types are used in the online examples. Although not proposed as standards, I document them here for completeness:
http://stemma.parallaxview.co/source-type/blog
An online blog. Parameters: [Author], Title, [Host], Blog, Date, URL, Accessed.
http://stemma.parallaxview.co/source-type/book
A printed book. Parameters: Author, Title, Publisher, PublisherAddr, Date, Page.
http://stemma.parallaxview.co/source-type/correspondence
Written correspondence. Parameters: From, To, Date.
http://stemma.parallaxview.co/source-type/folklore
Folklore or legend. Original source unknown. Parameters: Source, Date.
http://stemma.parallaxview.co/source-type/newspaper
Newspaper article. Parameters: [Author], Title, Paper, Date, Page, [Column].
http://stemma.parallaxview.co/source-type/testimony-1
First-hand testimony. Parameters: Source, Date.
http://stemma.parallaxview.co/source-type/testimony-2
Second-hand testimony. Parameters: Source-1, Date-1, Source-2, Date-2 (i.e. recollection as given to Source-1 by Source-2 on Date-2).
http://stemma.parallaxview.co/source-type/web-media
Online news service. Parameters: Author, Title, Publisher, PublisherAddr, Date, URL, Accessed.