 Usage:  y = pantime(z,{T})  
 
 Input:

  z                      Data matrix. First column: Identification number for 
                         cross section units (optional), Second column: depen- 
                         dent variable, Further columns: explanatory variables 
                         
  T                      (optional) for producing the identification numbers 
                         for a balanced data set 
                         
 Output:

  y                      Data matrix 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
