- Erik W. Grafarend, Joseph L. Awange, Linear and Nonlinear Models, 2012,
527 
- Erik W. Grafarend, Joseph L. Awange, Linear and Nonlinear Models, 2012,
89 - Erik W. Grafarend, Joseph L. Awange, Linear and Nonlinear Models, 2012,
263 - Erik W. Grafarend, Joseph L. Awange, Linear and Nonlinear Models, 2012,
411