{{sfn|Nations|G|A|2023|p=}}
* {{cite book | last=Nations | first=Food and Agriculture Organization of the United | last2=G | first2=Buonfiglio, | last3=A | first3=Lovatelli, | title=A practical guide on safe hookah diving | publisher=Food and Agriculture Organization of the United Nations | date=2023-01-18 | isbn=978-92-5-137476-4}}
<ref name="k402">{{cite book | last=Nations | first=Food and Agriculture Organization of the United | last2=G | first2=Buonfiglio, | last3=A | first3=Lovatelli, | title=A practical guide on safe hookah diving | publisher=Food and Agriculture Organization of the United Nations | date=2023-01-18 | isbn=978-92-5-137476-4 | page=}}</ref>