ample autocorrelation coefficients 
<A HREF = "sacf_d.m       ">sacf_d         </A>: demo of sacf() 
<A HREF = "sdiff.m        ">sdiff          </A>: generates a vector or matrix of lags
<A HREF = "sdummy.m       ">sdummy         </A>: creates a matrix of seasonal dummy variables
<A HREF = "selif.m        ">selif          </A>: select values of x for which cond is true
<A HREF = "seqa.m         ">seqa           </A>: produce a sequence of values
<A HREF = "seqm.m         ">seqm           </A>: produce a seq