(a) Follow the structure and order outlined in paragraphs (1) - (7) of this subsection when drafting a rule.
  (1) The highest subdivision within a rule is a "subsection." You need not subdivide below this level.
    (A) When there are two or more subsections, designate them with a lowercase letter in parenthesis. Example: (a), (b), etc.
    (B) When there is only one subsection in a section, omit the "(a)." This is referred to as an "implied (a)."
  (2) The rule subdivision below a subsection is called a "paragraph" and is designated by an Arabic number in parenthesis. Example: (1), (2), etc.
  (3) The rule subdivision below the paragraph is called a "subparagraph" and is designated by a capital letter in parenthesis. Example: (A), (B), etc.
  (4) The rule subdivision below the subparagraph is called a "clause" and is designated by a lowercase Roman numeral in parenthesis. Example: (i), (ii), etc.
  (5) The rule subdivision below the clause is called a "subclause" and is designated by a capitalized Roman numeral in parenthesis. Example: (I), (II), etc.
  (6) The rule subdivision below the subclause is called an "item" and is designated by a lowercase letter with a dash on both sides in parenthesis. Example: (-a-), (-b-), etc.
  (7) The rule subdivision below the item is called a "subitem" and is designated by an Arabic numeral with a dash on both sides in parenthesis. Example: (-1-), (-2-), etc.
(b) When drafting a rule, do not create a lone subdivision at any level, except for an "implied (a)." For example, a rule may not have a paragraph (1) without a (2), a subparagraph (A) without a (B), and so forth.

Source Note: The provisions of this §91.33 adopted to be effective March 23, 2003, 28 TexReg 2303