Environmental history focusing on nature's role in world history and the ways human systems of energy, agriculture, resource extraction, trade, and transportation have effected the environment over time and vice versa.
The venerable, time-tested guide to style, usage, and grammar--an indispensable reference informing the editorial canon with sound, definitive advice. Now in its 18th edition!
The Turabian guide, a simplified guide to the Chicago Manual of Style, is a popular choice. Be aware that Turabian and Chicago both offer two documentation systems. Be careful not to mix the two!