Clocks and sleep

Articles in SafetyLit
Y-Axis = Volume :: X-Axis = Issue
?=unknown status :: X=no issue published :: nn=articles from issue :: A=relevant article(s) IDed to add
S=searched, nothing relevant :: O=issue published but not yet searched :: C=combination issue

	1	2	3	4

1 (2019)	2	?	?	1
2 (2020)	3	2	?	2
3 (2021)	?	?	1	?
4 (2022)	2	?	?	2
5 (2023)	?	2	2	1
6 (2024)	2	?	?	?