Because these specific files are often associated with illegal activity (credential stuffing or hacking), formal academic papers do not exist for individual "MiX txt" downloads. However, you can find extensive research on the and forensic investigations related to these types of data breaches and email security. Relevant Research Papers & Resources
For a technical look at how organizations try to secure their domains, security.txt Revisited: Analysis of Prevalence and Conformity examines the adoption of standard security reporting methods. Download Mail Access MiX txt
Research on Features Analysis of All Email Components for Phishing Detection discusses how attackers lure victims into providing the credentials that eventually end up in these "MiX" lists. Defensive Best Practices Because these specific files are often associated with
The research (PDF) Managing Access to Confidential Documents compares popular tools like ProtonMail and Gmail to prevent unauthorized data downloads. Research on Features Analysis of All Email Components