to overcome this presumption by persuading the finder of fact, by a prepon derance of the evidence, that the income tax assessments are erroneous. See Sullivan v. United States, 618 F.2d 1001, 1008 (3d Cir.1980). Klimek has failed to offer any evidence that the tax assessments are incorrect in the amount the Government claims. He has never challenged in the Tax Court the Notices of Deficiency or the Certificates of Assessments and Payments for tax years 1980 through 1988 and 1990 through 1992. Nor has Klimek ever rebutted or even responded to the Government’s requests for admissions regarding tax years 1980 through 1988 and 1990 through 1992, except to return them with the words “Refused for Fraud” scrawled across them. See Lane v. United States, 328 F.2d 602, 603 (5th Cir.1964) (<HOLDING>). Given the fact that Klimek bears the burden
holding that a trial court may enter summary judgment for a nonmoving party under appropriate circumstances holding that a trial court is not required to convert a motion to dismiss to a motion for summary judgment where external evidence is submitted if the external evidence is irrelevant to the issue holding that if no countervailing evidence is introduced the trial court is  justified in fact required to enter summary judgment for the government the amount of the taxes proved to be due holding that summary judgment is appropriate when no issue of material fact exists and the court is reviewing administrative record for sufficiency of evidence holding that in ruling on a motion for summary judgment the trial court is limited to the grounds raised in the motion