See Whitehurst, 337 F.2d at 776 (“[I]f all of the factors which must necessarily be taken into account are established by proper evidence, there would appear to be no valid reason to judicially condemn, prohibit or outlaw the use of [the income capitalization approach].We do hold, however, in the instant case that the determination of the several elements or factors which were here relied upon was based upon pure speculation and was without objective evidential support.”); accord United States v. 69.1 Acres of Land (Sand Mountain), 942 F.2d 290, 293-94 (4th Cir. 1991) (discussing Whitehurst, 337 F.2d at 771); United States v. 47.14 Acres of Land in Polk Cty., 674 F.2d 722, 726 (8th Cir. 1982) (“[W]here such method is used all of the factors that must necessarily be taken into account should be established by proper evidence.