Sequences in countable nonstandard models of the natural numbers. - Steven C. Leth (Stud Logica, 1988)

Some nonstandard methods in combinatorial number theory. - Steven C. Leth (Stud Logica, 1988)

Descriptive Set Theory Over Hyperfinite Sets. - H. Jerome Keisler; Kenneth Kunen; Arnold W. Miller; Steven C. Leth (J. Symb. Log., 1989)

Meager Sets on the Hyperfinite Time Line. - H. Jerome Keisler; Steven C. Leth (J. Symb. Log., 1991)

Regions in the nonstandard plane that contain no standard points. - Steven C. Leth (J. Log. Anal., 2012)