Here's a link to the Zeus pocket engineering book.
There is a reference to the downloadable version but when I tried the link it did not work.
[URL unfurl="true"]https://www.google.com/search?client=firefox-b-d&q=Zeus+pocket+engineeering+book[/URL]
There is another link to a downloadable PDF but I did not try it :-
[URL unfurl="true"]https://pdfprodocs.vip/download/4735596-zeus-engineering-booklet-l[/URL]