[1] They are named after Joseph D. Horton and Mark N. Ellingham, their discoverers.

[3] The first counterexample to the Tutte conjecture was the Horton graph, published by Bondy & Murty (1976).

[4] After the Horton graph, a number of smaller counterexamples to the Tutte conjecture were found.

[7] At that time it was the smallest known counterexample to the Tutte conjecture.

The second Ellingham–Horton graph was published by Ellingham & Horton (1983) and is of order 54.