H. Kierstead, and W. Trotter. On-Line Algorithms, volume 7 of DIMACS Series in Discrete Mathematics and Theoretical Computer Science, page 85-92. DIMACS/AMS, (1991)
H. Kierstead, and W. Trotter. Planar Graphs, volume 9 of DIMACS Series in Discrete Mathematics and Theoretical Computer Science, page 85-93. DIMACS/AMS, (1991)