What is the correct abbreviation for the word “numbers”?

Question

What is the correct abbreviation for the words numbers and number?

• Nos.
• No.
• Nos
• No

Possible example usage:

1. "Number of guests" where the word number is abbreviated
2. "Numbers 10–15 are located in the top shelf."

Answer 1

It is highly unlikely that there is a global standard. It differs based on practice and the standards set by the relevant authorities (publishers and the like).

Ex: The Oxford Journal Instructions for Authors suggests (Sec. 2.3):

Abbreviations where the last letter of the singular word is not included take a full stop (vol., vols./ed., eds.). The abbreviation for number is no./nos. Abbreviated unit of measurements do not take a full stop (lb, mm, kg) and do not take a final 's' in the plural.

This is a suggestion from Cambridge Dictionary for use of no. as the abbreviation for number.

Answer 2

Cambridge dictionary only gives the abbreviation no. when number refers to a numeral, a position or identification, not a quantity, amount or calculation : http://dictionary.cambridge.org/dictionary/british/number_1

Therefore I understand "Number of guests" should not be abbreviated.