Charalambos A. Charalambides Non-central generalized <i>q</i>-factorial coefficients and <i>q</i>-Stirling numbers. 67-85 2004 275 Discrete Mathematics 1-3 http://dx.doi.org/10.1016/S0012-365X(03)00099-2 db/journals/dm/dm275.html#Charalambides04