1.asdoc reg Y1 X1 X2...,nest replace<br>
   asdoc reg Y2 X1 X2...,nest append<br>
2.reg Y1 X1 X2 <br>
   est store ols01<br>
   reg Y2 X1 X2 <br>
   est store ols02<br>
outreg2 [ols01 ols02 ] using M1,replace append<br>