 Usage:  (b,s)=sur(surlist1,surlist2)  
 
 Input:

  surlist1               list of matrices. If there are M equations then surlist1 
                         will be a list of M+1 matrices. The first matrix is comprised of 
                         the vectors of observations of the left-hand side variables. Each of the 
                         next M matrices consists of the observations of the right-hand-side 
                         variables of one of the M equations of the system. 
                         
  surlist2               list of string vectors. If there are M equations then surlist2 
                         will be a list of M+1 string (column) vectors. Each vector contains 
                         the names of the variables of the corresponding matrix from surlist1. 
                         
 Output:

  b                      vector, containing the generalized least squares coefficient estimates 
                         
  s                      vector, containing the estimated standard errors of the components of b 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
