1. Friedberg numbering in fragments of Peano arithmetic and α-recursion theory, the Journal of Symbolic Logic, vol. 78, no. 4, December 2013, pp. 1135-1163.
  2. Δ2 degrees without Σ1 induction, Israel Journal of Mathematics, Accepted. 
  3. Nonstandard models in recursion theory and reverse mathematics, with C. T. Chong and Yue Yang, the Bulletin of Symbolic Logic, volume 20, issue 02, pp. 170-200. © Wei Li 2014