Some cases hold that the government satisfies its burden under Holland if it negates each of these leads. E.g., Kramer v. Commissioner, 389 F.2d 236 (7th Cir. 1968). Here, however, Greene provided no leads for the government to negate.

1. Opening Net Worth As its starting point in proving Scott's net worth, see United States v. Hamilton, 620 F.2d 712, 714 (9th Cir. 1980); Kramer v. Commissioner, 389 F.2d 236, 238 (7th Cir. 1968), the government offered a letter dated April 16, 1968, that Scott wrote to his first wife, now Dorothy Humphrey, from whom he was then separated. In this letter, an apparent effort to arrange a property settlement, Scott described his assets and liabilities in detail.

Some cases have held that the government satisfies its burden if it negates each of these leads. E. g., Kramer v. Commissioner of Internal Revenue, 389 F.2d 236 (7th Cir. 1968). Here, however, appellant provided no leads for the government to negate.

We held there that as long as the district court properly supervised the use of the statements to refresh and that they were genuinely used only for that purpose, it was not error to permit the use of the otherwise unreliable and inadmissible recorded statements. See also, Allis-Chalmers Mfg. Co. v. City of Fort Pierce, Fla., 5 Cir. 1963, 323 F.2d 233; United States v. Baratta, 2 Cir. 1968, 397 F.2d 215; United States v. Tolbert, 7 Cir. 1966, 367 F.2d 778; Kramer v. Commissioner, 7 Cir. 1968, 389 F.2d 236; Hall Bartlett Prod. v. Republic Pictures Corp., 20 F.R.D. 625 (S.D.N.Y. 1957); see generally, III Wigmore §§ 758— 765 (Chadbourn Rev.). The technical prerequisites for refreshment were clearly met by Lacey.

This Court, upon review, will reverse only if such determination is clearly erroneous. Kramer v. Commissioner of Internal Revenue, 389 F.2d 236, 239 (7th Cir. 1968); Kessmar Construction Company v. Commissioner of Internal Revenue, 336 F.2d 865, 867 (9th Cir. 1964). "A finding is clearly erroneous when although there is evidence to support it, the reviewing court on the entire evidence is left with the definite and firm conviction that a mistake has been committed."

While a mere understatement of income does not conclusively establish fraud, a consistent pattern of understatement of substantial amounts of income over a period of years is not a mere understatement and is persuasive evidence of a fraudulent intent to evade taxes. Holland v. United States, 348 U.S. 121, 139, 75 S.Ct. 127, 99 L.Ed. 150 (1954). In Kramer v. Commissioner of Internal Revenue, 389 F.2d 236 (C.A.7, 1968), this Court held that this factor alone was sufficient to sustain a finding of fraud with intent to evade taxes. In addition, the evidence here shows that Hutchen failed to keep adequate books and records as required by section 6001 of the Code and Treasury Regulations section 1.6001-1(a) which applied to all years except 1953.

If the taxpayer claims specific nontaxable sources and the Commissioner negatives those sources, the Commissioner need neither investigate and negative all possible nontaxable sources nor prove a likely source of taxable income because it is reasonable to believe that the taxpayer making such claims did not have access to any other nontaxable sources. See Holland v. United States, 348 U.S. at 137-138; Kramer v. Commissioner, 389 F.2d 236 (7th Cir. 1968); Commissioner v. Thomas, 261 F.2d 643, 646 (1st Cir. 1958), rev'g and remanding T.C. Memo. 1955-46; DiLeo v. Commissioner, 96 T.C. at 873-874; Boone v. Commissioner, T.C. Memo. 1997-471, aff'd, 208 F.3d 212 (6th Cir. 2000). There is also no necessity of proof of a likely taxable source if the taxpayer advances no specific nontaxable sources and the Commissioner negatives all possible nontaxable sources.

Alternatively, where the taxpayer alleges a nontaxable source, respondent may satisfy his burden by disproving the nontaxable source so alleged. United States v. Massei, 355 U.S. 595 (1958); Kramer v. Commissioner, 389 F.2d 236, 239 (7th Cir. 1968), affg. a Memorandum Opinion of this Court. Respondent did not prove a likely source of petitioner's unreported income.

Similarly, in Rogers v. Commissioner, 111 F.2d 987, 989 (6th Cir. 1940) the court agreed that there had been taxpayer fraud where there were discrepancies of 100% and more between real net and reported income for three successive years, plus evidence of the taxpayer's prior criminal conviction for embezzlement of municipal funds. See also Kramer v. Commissioner, 389 F.2d 236 (7th Cir. 1968) (in proving underreporting by net worth analysis, government satisfactorily proved nonexistence of alleged substantial cash hoard); Kalil v. Commissioner, 271 F.2d 550, 551 (5th Cir. 1959) (taxpayer's underreported exceptionally large amounts of income for three successive years, but also admitted that in their liquor business they routinely made sales for prices in excess of ceiling prices then established by the government, in violation of the law); Brooks v. Commissioner, 82 T.C. 413, 432-33 (1984), aff'd without op., 772 F.2d 910 (9th Cir. 1985) (government utilized net worth analysis to show underreporting of taxes; taxpayer gave inadequate and inconsistent explanations for his alleged cash reserve, which the government fairly showed to be non-existent by other evidence); Habersham-Bey v. Commissioner, 78 T.C. 304, 312-14 (1982) (failure to file returns, coupled with numerous knowingly wrongful claimed tax exemptions, indicated taxpayer's fraudulent evasion of taxes). Here, the

Although no hard and fast rule can be laid down for invariable application, the predominant view today seems to be that within the sound discretion of the trial judge any memorandum or other object may be used as a stimulus to present memory, without restriction by rule as to authorship, guarantee of correctness, or time of making. Kramer v. Commission of Internal Revenue, 389 F.2d 236, 238 (1968) (Emphasis Added). In the case at bar, Foley testified as to past events but from his present recollection.