Under Fed.R.Evid. 803(18), learned treatises need not be acknowledged as reliable by the testifying expert. They are “not excluded by the hearsay rule . . . [t]o the extent called to the attention of an expert witness upon cross-examination [and] established as a reliable authority . . . by other expert testimony or by judicial notice.” They can be authenticated by an opposing party’s expert. Fournier v. Erickson, 242 F. Supp. 2d 318, 340 n.4 (S.D.N.Y. 2003) (admitting as learned treatises various document excerpts, on Rule 803(18) grounds, because two expected witnesses (whom the court treated, for this purpose, as experts) represented that they would testify to the reliability of the documents; the Court noted that it “would likely require supplemental affidavits by individuals selected by the parties: (1) commenting on either the standing of the authors in the industry, the popularity of the book, or the prominence of the specific excerpt's recommended practice; and (2) stating each affiant's professional background and the nature of any basis to offer such comment. The Court would then weigh the parties' submissions solely for purposes of determining the excerpt's reliability as a learned treatise.”); see also Costantino v. David M. Herzog, M.D., P.C., 203 F.3d 164, 173 (2d Cir. 2000) (“trial judge[s] should be liberal in allowing other proof of . . . authoritativeness, so long as it indicates that the [treatise] is recognized by the . . . profession”).