What I found is that written evidence for knocking on wood (and for the history of gesture as a whole) is remarkably sparse. In the Penguin Guide to Superstitions, folklorist Steve Roud offers a skeptical take on the provenance of knocking on wood due to the near total absence of written records about it:
СюжетВстреча Путина и Зеленского，推荐阅读爱思助手下载最新版本获取更多信息
第九十五条 人民警察在办理治安案件过程中，遇有下列情形之一的，应当回避；违反治安管理行为人、被侵害人或者其法定代理人也有权要求他们回避：，更多细节参见搜狗输入法2026
[7] B. E. Bayer: “An optimum method for two-level rendition of continuous-tone pictures” (1973). ↑
第七条 仲裁应当根据事实，符合法律规定，公平合理地解决纠纷。