1. Two notes on formal power series;Abhyankar,1956
2. R-endomorphisms of R[[X]] are essentially continuous;Eakin;Pacific J. Math.,1976
3. Zero divisors and nilpotent elements in power series rings;Fields,1971
4. R-automorphisms of R[[X]];Gilmer;Michigan Math. J.,1970
5. On ideal-adic topologies for a commutative ring;Gilmer;Enseign. Math.,1972