>Question 1:Is there a reference that lists all possible finite subgroups and their orders of $\mathrm{SO}(n)$ and $\mathrm{O}(n)$ for $n=4$ or even higher $n$ over the real numbers? I can only find incomplete lists on wikipedia, mathoverflow or other sources in the internet. >Question 2: Is there a computer algebra package that can list those finite subgroups up to some order? Maybe a package of GAP?