1. LBenjamin AT, Quinn JJ. Proof that Really Count. The Art of Combinatorial Proof. The Dolciani Mathematical Expositions, Mathematical Association of America; 2003. 27:209.
2. Lhttp://math.sun.ac.za/%20hproding/pdffiles/Double
3. LMiki J. A proof of Dixon's identity. J Integer Seq. 2016;19:1–5.
4. LMiki J. A proof of a famous identity concerning the convolution of the central binomial coefficients. J Integer Seq. 2016;19:1–10.