Merge branch 'master' of github.com:KWARC/bibs

Author: kohlhase

kwarc.bib

@@ -60,6 +60,26 @@ @STRING{wil
 @STRING{spring   = "Springer-Verlag"}
 @STRING{JWS = {Web Semantics: Science, Services and Agents on the World Wide Web}}
 
+@article{AppHak:epmfcI,
+  author = {Appel, Kenneth and  Haken, Wolfgang},
+  year = {1977},
+  title= {Every Planar Map is Four Colorable. I. Discharging},
+  journal = {Illinois Journal of Mathematics},
+  volume = {21},
+  number = {3},
+  pages = {429--490},
+  doi = {10.1215/ijm/1256049011}}
+
+@article{AppHakKoc:epmfcII,
+  author = {Appel, Kenneth and  Haken, Wolfgang and Koch, John},
+  year = {1977},
+  title= {Every Planar Map is Four Colorable. II. Reducibility},
+  journal = {Illinois Journal of Mathematics},
+  volume = {21},
+  number = {3},
+  pages = {491–-567},
+  doi = {10.1215/ijm/1256049012}}
+
 @online{EUAIAct:on,
   title = {The EU Artificial Intelligence Act -- Up-to-date developments and analyses of the EU AI Act},
   url = {https://artificialintelligenceact.eu/},