Certaine rules, directions, or aduertisments for this time of pestilentiall contagion: [electronic resource] : with a caueat to those that weare about their neckes impoisoned amulets as a preseruatiue from the plague: / first published for the behoofe of the city of London, and all other parts of the land at this time visited; by Francis Hering, D. in physicke, and fellow of the Colledge of Physitians in London.