Leica Camera And Lens Data Listing (Free)
Go down to the 6th book .
Leica Pocket Book (booklet with serial numbers)
and click on the PDF
Copy the PDF and print off any lists that you require.
Go to page 65 for the start of the lens listing (1933 onwards)
I have found the lens information very useful.
Leica II (1940)
5cm f1.5 Nikkor S.C. (Leica thread mount. 1949). - DDD's favourite early Ltm 5cm Nikkor lens.