A Ziegler-Natta type catalyst component can be produced by a process comprising contacting a magnesium dialkoxide compound with a halogenating agent to form a reaction product A, and contacting reaction product A with a first, second and third halogenating/titanating agents. Catalyst components, catalysts,...http://www.google.es/patents/US6930071?utm_source=gb-gplus-sharePatente US6930071 - Ziegler-natta catalyst for polyolefins
