diff --git a/free-programming-books-zh.md b/free-programming-books-zh.md
index b585cc2f..3b80156b 100644
--- a/free-programming-books-zh.md
+++ b/free-programming-books-zh.md
@@ -10,6 +10,7 @@
 * [C](#c)
 * [C++](#c-1)
 * [CoffeeScript](#coffeescript)
+* [Elasticsearch](#elasticsearch)
 * [Erlang](#erlang)
 * [Fortran](#fortran)
 * [Golang](#golang)
@@ -106,6 +107,8 @@
 * [CoffeeScript 中文手册](http://island205.github.io/tlboc/) (《The Little Book on CoffeeScript》中文版)
 * [CoffeeScript 编程风格指南](https://github.com/elrrrrrrr/coffeescript-style-guide/blob/master/README-ZH.md)
 
+### Elasticsearch
+* [Elasticsearch 权威指南](https://github.com/looly/elasticsearch-definitive-guide-cn) （《Elasticsearch the definitive guide》中文版）
 
 ### Erlang
 * [Erlang 并发编程](https://github.com/liancheng/cpie-cn) (《Concurrent Programming in Erlang (Part I)》中文版)
diff --git a/free-programming-books.md b/free-programming-books.md
index 2bb4e55c..aed6db0c 100644
--- a/free-programming-books.md
+++ b/free-programming-books.md
@@ -375,6 +375,7 @@ Original Source: [Free Programming books](http://stackoverflow.com/revisions/392
 * [Introduction to Probability](http://www.dartmouth.edu/~chance/teaching_aids/books_articles/probability_book/book.html) - Charles M. Grinstead and J. Laurie Snell
 * [Introduction to Probability and Statistics Spring 2014](http://ocw.mit.edu/courses/mathematics/18-05-introduction-to-probability-and-statistics-spring-2014/)
 * [Introduction to Statistical Thought](http://www.math.umass.edu/~lavine/Book/book.html) - Michael Lavine
+* [Kalman and Bayesian Filters in Python](https://github.com/rlabbe/Kalman-and-Bayesian-Filters-in-Python)
 * [Linear Algebra](https://www.math.ucdavis.edu/~linear/linear-guest.pdf)
 * [Linear Algebra: An Introduction to Mathematical Discourse](http://en.wikibooks.org/wiki/Linear_Algebra) - Jim Hefferon
 * [Linear Algebra, Theory And Applications](http://www.math.byu.edu/klkuttle/linearalgebra.pdf) - Kenneth Kuttler