diff --git a/CHANGELOG.md b/CHANGELOG.md
index 782e249..5f5c269 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,7 +3,12 @@ All notable changes to the SOTorrent dataset project will be documented in this
 
 ---
 
-## [2018-08-28] - Release for MSR Mining Challenge 2019, based on SO data dump 2018-06-05
+## [2018-09-23] - Second release for MSR Mining Challenge 2019, based on SO data dump 2018-09-05
+
+* Update to Stack Overflow data dump 2018-09-05
+* Update `PostReferenceGH` (retrieved on 2018-09-23)
+
+## [2018-08-28] - First release for MSR Mining Challenge 2019, based on SO data dump 2018-06-05
 
 * Improve URL extraction (e.g., exclude matches in Markdown inline code, exclude invalid links)
 
diff --git a/bigquery/1_extract_so_references.sql b/bigquery/1_extract_so_references.sql
index 238c4f5..910847e 100644
--- a/bigquery/1_extract_so_references.sql
+++ b/bigquery/1_extract_so_references.sql
@@ -1,4 +1,4 @@
---- Status: 2018-08-28
+--- Status: 2018-09-23
 --- Execute this in BigQuery
 
 --- select all source code lines of text files that contain a link to Stack Overflow
@@ -31,7 +31,7 @@ FROM (
 )
 WHERE REGEXP_CONTAINS(line, r'(?i:https?://stackoverflow\.com/[^\s)\.\"]*)');
 
-=> gh_so_references_2018_08_28.matched_lines
+=> gh_so_references_2018_09_23.matched_lines
 
 
 --- join with table "files" to get information about repos
@@ -44,11 +44,11 @@ SELECT
   size,
   url,
   line
-FROM `sotorrent-org.gh_so_references_2018_08_28.matched_lines` as lines
+FROM `sotorrent-org.gh_so_references_2018_09_23.matched_lines` as lines
 LEFT JOIN `bigquery-public-data.github_repos.files` as files
 ON lines.file_id = files.id;
 
-=> gh_so_references_2018_08_28.matched_files
+=> gh_so_references_2018_09_23.matched_files
 
 
 --- normalize the SO links to (http://stackoverflow.com/(a/q)/<id>)
@@ -72,9 +72,9 @@ SELECT
     ELSE url
   END as url,
   line
-FROM `sotorrent-org.gh_so_references_2018_08_28.matched_files`;
+FROM `sotorrent-org.gh_so_references_2018_09_23.matched_files`;
 
-=> gh_so_references_2018_08_28.matched_files_normalized
+=> gh_so_references_2018_09_23.matched_files_normalized
 
 
 --- extract post id from links, set post type id, and extract file extension from path
@@ -96,11 +96,11 @@ SELECT
   END as post_type_id,
   url,
   line
-FROM `sotorrent-org.gh_so_references_2018_08_28.matched_files_normalized`
+FROM `sotorrent-org.gh_so_references_2018_09_23.matched_files_normalized`
 WHERE
   REGEXP_CONTAINS(url, r'(http:\/\/stackoverflow\.com\/(?:a|q)\/[\d]+)');
   
-=> gh_so_references_2018_08_28.matched_files_aq
+=> gh_so_references_2018_09_23.matched_files_aq
 
 
 --- use camel case for column names, add number of copies, and remove line content for export to MySQL database
@@ -108,7 +108,7 @@ WHERE
 WITH
 	copies AS (
 		SELECT file_id, count(*) as copies
-		FROM `sotorrent-org.gh_so_references_2018_08_28.matched_files_aq`
+		FROM `sotorrent-org.gh_so_references_2018_09_23.matched_files_aq`
 		GROUP BY file_id
 	)
 SELECT
@@ -123,16 +123,16 @@ SELECT
   post_type_id as PostTypeId,
   url as SOUrl,
   CONCAT('https://raw.githubusercontent.com/', repo_name, "/", branch, "/", path) as GHUrl
-FROM `sotorrent-org.gh_so_references_2018_08_28.matched_files_aq` files
+FROM `sotorrent-org.gh_so_references_2018_09_23.matched_files_aq` files
 JOIN copies
 ON files.file_id = copies.file_id;
 
-=> gh_so_references_2018_08_28.PostReferenceGH
+=> gh_so_references_2018_09_23.PostReferenceGH
 
 
 
 ###################################################################
-# the following tables are not present in gh_so_references_2018_08_28
+# the following tables are not present in gh_so_references_2018_09_23
 # will only be created on demand
 ###################################################################
 
@@ -155,7 +155,7 @@ WITH
       parent_id as ParentId,
 	  SOUrl,
 	  GHUrl
-    FROM `sotorrent-org.gh_so_references_2018_08_28.PostReferenceGH` ref
+    FROM `sotorrent-org.gh_so_references_2018_09_23.PostReferenceGH` ref
     LEFT JOIN `bigquery-public-data.stackoverflow.posts_answers` a
     ON ref.PostId = a.id
     WHERE PostTypeId=2
@@ -180,7 +180,7 @@ FROM answers
 LEFT JOIN `bigquery-public-data.stackoverflow.posts_questions` q
 ON answers.ParentId = q.id;
 
-=> gh_so_references_2018_08_28.PostReferenceGH_Answers
+=> gh_so_references_2018_09_23.PostReferenceGH_Answers
 
 
 #standardSQL
@@ -192,9 +192,9 @@ SELECT
   CommentCount,
   Score,
   ParentViewCount
-FROM `sotorrent-org.gh_so_references_2018_08_28.PostReferenceGH_Answers`;
+FROM `sotorrent-org.gh_so_references_2018_09_23.PostReferenceGH_Answers`;
 
-=> gh_so_references_2018_08_28.PostReferenceGH_Answers_R
+=> gh_so_references_2018_09_23.PostReferenceGH_Answers_R
 
 
 --- retrieve info about referenced SO questions
@@ -214,12 +214,12 @@ SELECT
   view_count as ViewCount,
   SOUrl,
   GHUrl
-FROM `sotorrent-org.gh_so_references_2018_08_28.PostReferenceGH` ref
+FROM `sotorrent-org.gh_so_references_2018_09_23.PostReferenceGH` ref
 LEFT JOIN `bigquery-public-data.stackoverflow.posts_questions` q
 ON ref.PostId = q.id
 WHERE PostTypeId=1;
 
-=> gh_so_references_2018_08_28.PostReferenceGH_Questions
+=> gh_so_references_2018_09_23.PostReferenceGH_Questions
 
 
 #standardSQL
@@ -231,6 +231,6 @@ SELECT
   CommentCount,
   Score,
   ViewCount
-FROM `sotorrent-org.gh_so_references_2018_08_28.PostReferenceGH_Questions`;
+FROM `sotorrent-org.gh_so_references_2018_09_23.PostReferenceGH_Questions`;
 
-=> gh_so_references_2018_08_28.PostReferenceGH_Questions_R
+=> gh_so_references_2018_09_23.PostReferenceGH_Questions_R
diff --git a/sotorrent/README.md b/sotorrent/README.md
index e3db89d..5bbdbb5 100644
--- a/sotorrent/README.md
+++ b/sotorrent/README.md
@@ -12,6 +12,6 @@
 
 ## Data
 
-The Stack Overflow data has been extracted from the official [Stack Exchange data dump](https://archive.org/details/stackexchange) released 2018-06-05.
+The Stack Overflow data has been extracted from the official [Stack Exchange data dump](https://archive.org/details/stackexchange) released 2018-09-05.
 
-The GitHub references have been retrieved from the [Google BigQuery GitHub data set](https://cloud.google.com/bigquery/public-data/github) on 2018-08-28.
+The GitHub references have been retrieved from the [Google BigQuery GitHub data set](https://cloud.google.com/bigquery/public-data/github) on 2018-09-23.