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:
Варвара Кошечкина (редактор отдела оперативной информации)，更多细节参见safew官方下载
Цены на нефть взлетели до максимума за полгода17:55，推荐阅读同城约会获取更多信息
·研究团队邀请了99位PTSD不同程度患者分为三组，包括多种职业和经历，其中一组游玩《俄罗斯方块》，其他组采取传统音乐等疗法，进行对比试验。，这一点在Line官方版本下载中也有详细论述