diff --git a/css-system-font-stack.md b/css-system-font-stack.md
index 5f2126425..19c2901ac 100644
--- a/css-system-font-stack.md
+++ b/css-system-font-stack.md
@@ -3,6 +3,6 @@ title: "CSS: System font stack"
 category: CSS
 ---
 
-```
-font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
-```
+> font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
+
+Reference: <https://medium.com/design/system-shock-6b1dc6d6596f>
diff --git a/docker-compose.md b/docker-compose.md
new file mode 100644
index 000000000..889380f84
--- /dev/null
+++ b/docker-compose.md
@@ -0,0 +1,23 @@
+---
+title: docker-compose
+category: Devops
+---
+
+```yaml
+# docker-compose.yml
+version: '2'
+
+services:
+  web:
+    build: .
+    ports:
+     - "5000:5000"
+    volumes:
+     - .:/code
+  redis:
+    image: redis
+```
+
+```sh
+docker-compose up
+```
diff --git a/ets.md b/ets.md
index f388085a3..013b34dc4 100644
--- a/ets.md
+++ b/ets.md
@@ -36,3 +36,4 @@ iex> table = :ets.new(:my_table, [:set, :protected])
 ## References
 
 * <http://erlang.org/doc/man/ets.html>
+* <http://learnyousomeerlang.com/ets>