books.google.co.ukhttp://books.google.co.uk/books/about/Thesaurus_%C3%A6nigmaticus_or_A_collection_o.html?id=0xsFAAAAQAAJ&q=%22%C3%A6nigma%22&utm_source=gb-gplus-shareThesaurus ænigmaticus: or, A collection of the most ingenious and diverting ænigma's or riddles
