“Secure Deletion of Data from Magnetic and Solid-State Memory” – This whitepaper describes some of the methods available to recover erased data and presents schemes to make this recovery significantly more difficult.
You can download it from the following link: https://packetstormsecurity.com/files/download/13850/secure_del.html
Source: https://packetstormsecurity.com/files/13850/secure_del.html.html