Headings

Headings should be used to indicate the hierarchical structure of the text. There should normally be not more than four levels, including the chapter headings as the first level. For example, 

Section 1

1.1

1.1.1

1.1.1.1

Each level shall be distinguished from the others by position or typography, or both. The space that precedes and follows a heading shall be not less than the space between paragraphs. Headings shall not normally be centred.

A table of content should be provided at the beginning.