This is a preliminary version. More details about the STD system can be found here:
http://raiith.iith.ac.in/5161/1/1476.PDF
https://pdfs.semanticscholar.org/d235/7870f53eed854fc65b6b0f78fc62b968f0c6.pdf
http://raiith.iith.ac.in/5161/1/1476.PDF
https://pdfs.semanticscholar.org/d235/7870f53eed854fc65b6b0f78fc62b968f0c6.pdf