In the study of classic boxing incidents,

I have wondered how many times a ref has been replaced during a fight either because of health issues or being hit by one of the fighters during the match and unable to continue?

The most famous incident is Robinson-Maxim, in which referee Ruby Goldstein had to be replaced late in the fight after the 10th round because of heat exhaustion. (It was known to be 100 degrees+ that night.) Robinson who had been ahead in the fight, also could not continue after the 13th round and Maxim won by 14th round TKO.

Another is Leonard-Shields, when Shields caught the ref with a punch in the 9th round. The ref couldn't continue to ref and one of the judges had to take over to ref the 10th round.

In what other fights has this happened?

Jack