All notifications shall be made in writing. The notifications shall be considered as duly made, if sent by registered mail, fax or personally delivered to the postal addresses of the PARTIES.

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http://www.elinfonet.com/prov/38
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Any notice intended for you hereunder shall be deemed duly served if delivered to you personally, or duly dispatched by prepaid telegram or certified or registered mail, addressed to you at the address hereinabove set forth. Any notice intended for the company shall be deemed duly served if delivered personally to the company or duly dispatched by prepaid telegram or certified or registered mail addressed to the company as follows: