Isomorphism types of the hyperarithmetic sets Ha. - George C. Nelson (Notre Dame J. Formal Log., 1978)

Model Companions and k-Model Completeness for the Complete Theories of Boolean Algebras. - J. Mead; George C. Nelson (J. Symb. Log., 1980)

Logic of Reduced Power Structures. - George C. Nelson (J. Symb. Log., 1983)

Addendum to "Logic of Reduced Power Structures". - George C. Nelson (J. Symb. Log., 1983)

Other logics for (equational) theories. - George C. Nelson (Algebraic Logic and Universal Algebra in Computer Science, 1988)

Constructive Ultraproducts and Isomorphisms of Recursively Saturated Ultrapowers. - George C. Nelson (Notre Dame J. Formal Log., 1992)

Preservation Theorems Without Continuum Hypothesis. - George C. Nelson (Stud Logica, 1998)