Current Sources are   

 I1 = - j1.20 per unit
 I2 = -0.72 - j0.96 per unit
 I3 = - j1.20 per unit 

 
 Self-admittances are   

 Y11 = - j9.80 per unit
 Y22 = - j8.30 per unit
 Y33 = - j15.30 per unit
 Y44 = - j18.00 per unit

 
 Mutual admittances are   

 Y12 = Y21 = 0.00 per unit
 Y13 = Y31 = j4.00 per unit
 Y14 = Y41 = j5.00 per unit
 Y23 = Y32 = j2.50 per unit
 Y24 = Y42 = j5.00 per unit
 Y34 = Y43 = j8.00 per unit 

 
 Current Vector =   
 
  - 1.2i                    
  - 0.7200017 - 0.9599987i  
  - 1.2i                    
    0                       
 
 Bus admittance matrix =   
 
  - 9.8i    0       4.i      5.i   
    0     - 8.3i    2.5i     5.i   
    4.i     2.5i  - 15.3i    8.i   
    5.i     5.i     8.i    - 18.i