I have found no less thanfour diaries for 1973, all of them incomplete:

1. My “real diary”, the one I kept from 1963, in this case volume 9, started on 10 June 1970 and kept continuously only until 1 October 1970. There are about 30 entries for 1973, spread between April and October.
2. A pocket “business man's diary” from Collins, in English and one opening per week. I appear not to have used this much for making notes
3. A pocket diary published by BASF in German, also one opening per week. There are some relevant entries here.
4. A UNIVAC diary that I presumably got when I joined the company, in German and one opening for 2 months. The notes are mainly work-related.