Wikipedia:Articles for deletion/Quaternionic matrix
Finding a source for this seems easy, e.g. ''http://books.google.com/books?id=ybQrAAAAYAAJ Quaternionic and Clifford calculus for physicists and engineers'', which has a section specifically about this notion.  Please see 
— User:Colonel, 08:49, 8 September 2010 (UTC)
Stance: keep
Cited policy: WP:BEFORE (Wikipedia:Articles for deletion)