feat: wrote a bit on anforderungserfassung

dexes/literature.bib

@@ -203,3 +203,27 @@
   author = {Christoph Ebert},
   publisher = {dpunkt Verlag}
 }
+
+@book{bib:basiswissen-re,
+  author={Pohl, Klaus and Rupp, Chris},
+  title={Basiswissen Requirements Engineering},
+  subtitle={Aus- und Weiterbildung nach IREB-Standard zum "Certified Professional for Requirements Engineering" : Foundation Level nach IREB-Standard},
+  edition={4., {\"u}berarbeitete Auflage},
+  publisher={dpunkt.verlag},
+  address={Heidelberg},
+  year={2015},
+  pages={1 Online-Ressource (xix, 171 Seiten)},
+  language={ger},
+  isbn={978-3-86491-673-1 and 978-3-86491-674-8 and 3-86491-674-7},
+  note={Description based upon print version of record},
+  keywords={CPRE},
+  url={https://ebookcentral.proquest.com/lib/ub-heidelberg/detail.action?docID=2029882},
+  library={UB},
+}
+
+@article{bib:kleine-re-fibel,
+  title = {Die kleine RE-Fibel},
+  volume = {3},
+  year = {2016},
+  author = {{Die SOPHISTen}},
+}