diff --git a/Bibliography.md b/Bibliography.md
index 63db3f0..9ce420c 100644
--- a/Bibliography.md
+++ b/Bibliography.md
@@ -17,6 +17,8 @@ Here are some papers that are potentially of interest.
 * [On the Security of Hash Function Combiners](http://tuprints.ulb.tu-darmstadt.de/2094/1/thesis.lehmann.pdf) Anja Lehman's dissertation on hash function combiners
 * [web page on multiple encryption](http://www.ciphersbyritter.com/GLOSSARY.HTM#MultipleEncryption) by John Ritter
 * [Chosen-Ciphertext Security of Multiple Encryption](http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.65.8477) by Dodis, Katz 2005 ; combining two or more ciphers together
+* [Folklore, practice and theory of robust combiners](https://sites.google.com/site/amirherzberg/tolerant.pdf?attredirects=0) by Amir Herzberg
+* [On the security of multiple encryption](http://www.cs.purdue.edu/homes/ninghui/courses/Spring04/homeworks/p465-merkle.pdf) by Merkle and Hellman, 1981
 
 ### Public Key Cryptography