On common fixed and periodic points of commuting functions
Continuous commuting selfmaps of \([0,1]\) are considered. It is known that they need not have a common fixed point. However, there is an open problem if they have a common periodic point. Although the paper does not solve this problem, it gives some useful results in this direction and also a condition under which two continuous functions must have a unique common fixed point.
scientific article; zbMATH DE number 1140269