The Editor’s Manual
Free learning resource on English grammar, punctuation, usage, and style.
A period indicates a longer pause than a comma or a semicolon. Use a period to end a sentence and to mark the end of a thought or fragment. Also use periods in abbreviations and to separate initials before a surname.
A list may be horizontal or vertical. List elements must be consistently punctuated and capitalized. Use a numbered list when the sequence or number of items is important; otherwise, use bullets.