Is establishing authorship necessary to properly authenticate a writing?

was motivated by it in his actions." ( Ibid. ) In such instances, where authorship is irrelevant and the sole issues are whether a witness "receive[d] th[e] material, and if so what effect, if any, did it have on [his] mind[ ]," we have confirmed that establishing authorship is not necessary to properly authenticate a writing.⁹ ( People v. Marsh (1962) 58 Cal.2d 732, 740, 26 Cal.Rptr. 300, 376 P.2d 300 [discussing

[476 P.3d 269]