1) Acta Cryst. (1975). B31, 2663
The Crystal and Molecular Structure of 1-Piperoylpiperidine
By Marc Grynpas and Peter F. Lindley

2) Effect of piperine on the epididymis of adult male rats
By S. C. D'cruz, P. P. Mathur

3) Journal of the Chemical Society, Perkin Transactions 1,  (19), 2393-2397; 2001
Three-component synthesis of (E)-a ,b -unsaturated amides of the piperine family     
By Schobert, Rainer; Siegfried, Sven; Gordon, Gary J.   

Sigma Aldrich

Thomson Healthcare

Pepper plant pictures from www.ucmp.berkeley.edu