1. Complete models of differential fields;Blum;Trans. Amer. Math. Soc.,1969
2. Extending differential specializations;Blum;Proc. Amer. Math. Soc.,1970
3. Elements of Mathematics;Bourbaki,1972
4. An Introduction to Differential Algebra;Kaplansky,1957
5. Commutative Rings;Kaplansky,1974