الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
In order to unify gravitational and electromagnetic fields and /or to remove singularities from the classical vacuum solutions, several authors, Wey1 [72], Bach [3],Eddington [22], Lanczos [37], Buchdahl [9]-[16], Stephenson [65], Havas [29],Stelle [64]. Schimming [55]-[57] and others invented and investigated a modification of the Einstein-Hilbert gravitational Langrangian, which leads to Einstein general theory of relativity; namely, they added curvature squared terms, R2,|Ric|2 , |Riem|2 to the latter, where we abbreviate |Ric|2:= RaBRaB, |Riem|2:=RaBµvRabµv . Due to the fact that Gauss-Bonnet Expression B := R2-4|Ric|2+ |Riem|2, are only of second order [63].
The vacuum field equations from variational principle for a scalar field ø and for an electromagnetic potential A according to the Kaluza-Klein nrinciple from the quadratic lagrangian are derived. The type of the vacuum field equations in suitable gauge is discussed.