diff --git a/01_phonetics/assignment01.md b/01_phonetics/assignment01.md
index 4c5e2c5..2c16681 100644
--- a/01_phonetics/assignment01.md
+++ b/01_phonetics/assignment01.md
@@ -2,10 +2,13 @@
 title: "Linguistics for Cognitive Science: Assignment 1"
 author: 
     - Felicia Saar
-    - David-Elias Künstle
+    - David-Elias Künstle (3822829)
 date: \today
 
 documentclass: article
+bibliography: references.bib
 ---
 
 __If a language has fewer consonants, will the consonants that it does have be simpler and easier to articulate?__
+
+@wals-1
diff --git a/01_phonetics/makefile b/01_phonetics/makefile
index 06eb135..a550fee 100644
--- a/01_phonetics/makefile
+++ b/01_phonetics/makefile
@@ -1,10 +1,10 @@
 all: assignment01.pdf
 
 show: assignment01.pdf 
-	xdg-open $< &
+	xdg-open $< 
 
 clean:
 	rm *.pdf
 
 %.pdf: %.md
-	pandoc -o $@ $<
+	pandoc  --filter pandoc-citeproc -o $@ $<
diff --git a/01_phonetics/references.bib b/01_phonetics/references.bib
new file mode 100644
index 0000000..18b7271
--- /dev/null
+++ b/01_phonetics/references.bib
@@ -0,0 +1,12 @@
+@inbook{wals-1,
+  address   = {Leipzig},
+  author    = {Ian Maddieson},
+  booktitle = {The World Atlas of Language Structures Online},
+  editor    = {Matthew S. Dryer and Martin Haspelmath},
+  publisher = {Max Planck Institute for Evolutionary Anthropology},
+  title     = {Consonant Inventories},
+  url       = {http://wals.info/chapter/1},
+  year      = {2013}
+}
+
+