I am currently studying the incredible 1960 paper "On quadruple systems" by Haim Hanani, and stumbled upon his Wikipedia entry which states that Hanani died in April of 1991, but not on which day.
Then I did some researching and found an image of a gravesite that I suspect is his. If it is, then his death date would be 23rd of Nisan, 5751 (Hebrew date) = April 7, 1991 (Gregorian date). The only thing that looks strange to me is that on the grave, the birth date is given as 22nd of Elul, 5672 = September 4, 1912, which contradicts the birth date of September 11, 1912 given in the Wikipedia entry.
Doe anyone here have access to additional resources that give the exact dates of birth and death? Is the WP article wrong about the birth date? Or was there more than one person named Haim Hanani? Professor Hanani surely deserves a "proper" WP entry.