diff --git a/01_phonetics/assignment01.md b/01_phonetics/assignment01.md
index 2c16681..3f02331 100644
--- a/01_phonetics/assignment01.md
+++ b/01_phonetics/assignment01.md
@@ -7,8 +7,24 @@
 
 documentclass: article
 bibliography: references.bib
----
+geometry: "margin=1in"
+urlcolor: black
 
-__If a language has fewer consonants, will the consonants that it does have be simpler and easier to articulate?__
+...
 
-@wals-1
+**If a language has fewer consonants, will the consonants that it does have be simpler and easier to articulate?**
+
+With their *size principle* @Lindblom-and-Maddieson-1988 suggest a positive correlation between the a language's consonant inventory size and consonant simplicity. 
+A consonant is simpler if he is easier to pronounce and to distinguish from other.
+The intuitive explanation for the size principle is kind of a consonant darwinism: 
+If a consonant is hard to pronounce speaker will simplify or even omit them. If a consonant is hard to distinguish of another, they will probably melt together over time. 
+Beside this intuitive explanation we can find a lot of examples in the world's language which support the size principle, small inventories with just simple consonants or complex consonants only in large inventories.  
+
+The *glottalized consonants* require "more intricate coordination of the actions of the larynx with the actions of the articulators in the mouth than many of the more common sounds" [@wals-7] and are therefore not simple or complex consonants. 
+For example the sub group of *ejective stops* require complete closing of the vocal folds and upwards movement of the larynx exacly timed so that the air will be compressed and a explosive noise on opening the mouth apears. [@wals-7] 
+Even there are three different subgroups of glottalized consonants over $70$% of the languages ($409$ out of $567$) have non at all. 
+The amount of complex consonants in the consonant inventory classes mirror perfectly what we expect from the size principe. $66.7$% of the large consonant inventory class ($34$ or more consonants) contain glottalized consonants, but only $8.7$% of the small consonant inventory size class ($6$ to $14$ consonants) do [see @wals-7, Table 2].
+
+**HIER MUSS NOCH EINE CONTRA REFERENCE HIN !!!**
+
+**References**
diff --git a/01_phonetics/makefile b/01_phonetics/makefile
index a550fee..6115229 100644
--- a/01_phonetics/makefile
+++ b/01_phonetics/makefile
@@ -4,7 +4,7 @@
 	xdg-open $< 
 
 clean:
-	rm *.pdf
+	rm assignment01.pdf
 
 %.pdf: %.md
 	pandoc  --filter pandoc-citeproc -o $@ $<
diff --git a/01_phonetics/references.bib b/01_phonetics/references.bib
index 18b7271..4137def 100644
--- a/01_phonetics/references.bib
+++ b/01_phonetics/references.bib
@@ -9,4 +9,27 @@
   year      = {2013}
 }
 
+@inbook{wals-7,
+  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     = {Glottalized Consonants},
+  url       = {http://wals.info/chapter/7},
+  year      = {2013}
+}
 
+@incollection{Lindblom-and-Maddieson-1988,
+  address    = {London},
+  author     = {Lindblom, Björn and Maddieson, Ian},
+  booktitle  = {Language, Speech and Mind},
+  editor     = {Li, C. and Hyman, L. M.},
+  pages      = {62-78},
+  publisher  = {Routledge},
+  title      = {Phonetic Universals in Consonant Systems},
+  year       = {1988},
+  iso_code   = {},
+  olac_field = {},
+  wals_code  = {}
+}