Update Readme.md

Readme.md

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 Olivier Zeyen, Romain Péchoux, Emmanuel Jeandel, and Emmanuel Hainry
 
+## References
+
 [^HP15]: Emmanuel Hainry and Romain Péchoux. Objects in polynomial time. In APLAS 2015, LNCS, pages 387–404. Springer, 2015.
 [^HP18]: Emmanuel Hainry and Romain Péchoux. A type-based complexity analysis of object oriented programs. Information and Computation, 261:78–115, 2018.
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