Elder, Murray

• The Electronic Journal of Combinatorics Volume 13 (2006) - Research Papers
  Permutations Generated by a Stack of Depth 2 and an Infinite Stack in Series
  Abstract  PDF
• The Electronic Journal of Combinatorics Volume 22, Issue 2 (2015) - Papers
  Permutations Generated by a Depth 2 Stack and an Infinite Stack in Series are Algebraic
  Abstract  PDF  final version  Official source
• The Electronic Journal of Combinatorics Volume 28, Issue 1 (2021) - Papers
  $k$-Pop Stack Sortable Permutations and $2$-Avoidance
  Abstract  PDF