Merge pull request #176 from catgonzftw1/patch-4

Update a missing reference from #159

docs/_bibliography/references.bib

@@ -431,3 +431,18 @@ @book{harmsen_henk_explanatory_2013
 	author = {Harmsen, Henk and Keitel, Christian and Schmidt, Christoph and Schoger, Astrid and Schrimpf, Sabine and Stürzlinger, Martin and Wolf, Stefan},
 	year = {2013},
 }
+
+@article{Cousijn2021,
+  title = {Connected Research: The Potential of the PID Graph},
+  volume = {2},
+  ISSN = {2666-3899},
+  url = {http://dx.doi.org/10.1016/j.patter.2020.100180},
+  DOI = {10.1016/j.patter.2020.100180},
+  number = {1},
+  journal = {Patterns},
+  publisher = {Elsevier BV},
+  author = {Cousijn,  Helena and Braukmann,  Ricarda and Fenner,  Martin and Ferguson,  Christine and van Horik,  René and Lammey,  Rachael and Meadows,  Alice and Lambert,  Simon},
+  year = {2021},
+  month = jan,
+  pages = {100180}
+}