Tsikouras, P.

• The Electronic Journal of Combinatorics Volume 18, Issue 1 (2011) - Papers
  General Results on the Enumeration of Strings in Dyck Paths
  Abstract  PDF
• The Electronic Journal of Combinatorics Volume 12 (2005) - Research Papers
  Counting peaks and valleys in $k$-colored Motzkin paths
  Abstract  PDF