Here are some of his appearances in dragon ball
Personally I don't know if Toriyama version of superman was created on purpose to make fun of the real superman or was it just done to pay him respect. Because I mean Toriyama grew up during the silver age superman era. If the comics back in the days where translated into Japanese version, do you think he would have read or known what superman was really capable, such as patching up black holes or sneezing solar systems? And I feel like Toriyama compared to many other mangaka's tends to have more respect to his own work atleast back then.
My question do you think Toriyama believe that Goku was actually strongest than superman? And do you think he actually watched the whole death battle on you tube that screw attack did, which either he might have found by accident or someone from work or friends told him about it?
I personally would love to see what Toriyama has to say about this whole Goku vs Superman debate. I want him to tell us what are Gokus actual limits, And with the whole Superman killing SSJGODSSJ Goku so easily, do you think this is what would have happened in an actual fight or not?