Four Pages are Necessary and Sufficient for Planar Graphs (Extended Abstract) Mihalis Yannakakis 104-108 conf/stoc/STOC18 1986 STOC db/conf/stoc/stoc86.html#Yannakakis86 https://doi.org/10.1145/12130.12141 https://www.wikidata.org/entity/Q55920247