Where Can I Find The Whole Set of "Endangered!" Reference Books?

So, I just got the 17th volume of Wildlife and Plants of the world and in the Further Research page it says in one of the books in this page was Endangered! Which was a book also made by Marshall Cavendish which it came in 18 volumes and the picture is the proof of it existing. So where can I find a physical copy of the whole set because I'd like to have it in my collection now. As I do have the original version of The International Wildlife Encyclopedia and the entire set if that which I have got on Christmas Eve of 2022.