Directed Tree-Width. - Thor Johnson; Neil Robertson 001; Paul D. Seymour; Robin Thomas 001 (J. Comb. Theory B, 2001)

Spanning trees with many leaves. - Guoli Ding; Thor Johnson; Paul D. Seymour (J. Graph Theory, 2001)

Generating Internally Four-Connected Graphs. - Thor Johnson; Robin Thomas 001 (J. Comb. Theory B, 2002)

Excluding A Grid Minor In Planar Digraphs. - Thor Johnson; Neil Robertson 001; Paul D. Seymour; Robin Thomas 001 (CoRR, 2015)