Deletion of METATYPE1

Comment: The article has a book reference that is both reliable and independent and is 8 pages long in coverage of this topic. There are bunch of articles in Google Scholar as well, and some don't seem to be from the authors of the software  (listed in this article), e.g. http://www.edutex.tug.org/TUGboat/tb29-1/tb91hoeppner.pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.93.1240&rep=rep1&type=pdf. Seems enough for 
Stance: keep
Cited policy: Wikipedia:Notability (WP:N)