Appendices should be numbered A, B, etc. All sections must have a short descriptive title, which should be capitalized. Equations that are important, long, and complex should be set off from the text and should be numbered consecutively with arabic numbers within parentheses, these numbers to be placed to the extreme right of the equations. A standard typesetting procedure is followed by the production staff. However, authors should observe the following simple rules to help clarify the content of mathematical material.
Variables are to be set in normal italic, vectors in boldface.
Physical constants such as the speed of light or the Boltzmann constant are also set in normal italic. The best place for a break is right before an operator or sign of relation. These signs should begin the next line of the equation. There are footnotes to text material, which should be restricted as far as possible, and which should be designated by a numerical superscript in parentheses to avoid any possible confusion with mathematical expressions. They should be placed at the foot of the relevant page.