 Usage:  {d3sls,cov3,d2sls} = seq(seqlist1,seqlist2)  
 
 Input:

  seqlist1               list of matrices. If there are M equations then seqlist1 
                         will be a list of M+2 matrices. The first matrix is comprised of 
                         the vectors of observations of the left-hand side variables. The 
                         next M matrices consist of the observations of the right-hand-side 
                         variables of the M equations. The last matrix contains the observations 
                         of the exogenous variables of the system. 
                         
  seqlist2               list of string vectors. If there are M equations then seqlist2 
                         will be a list of M+2 string (column) vectors. Each vector contains 
                         the names of the variables of the corresponding matrix from seqlist1. 
                         
 Output:

  d3sls                  3-stage lest squares coefficient estimates 
                         vector 
                         
  cov3                   estimated covariance matrix of the 3sls-estimator 
                         matrix 
                         
  d2sls                  2-stage lest squares coefficient estimates 
                         vector 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
