Either Executive or the Company may terminate Executive's employment, after having established Executive's Disability, by giving notice of his or its intention to terminate Executive's employment. Executive shall be deemed to have a "Disability" for purposes of this Agreement if Executive has any medically-determinable physical or mental impairment that has lasted for a period of not less than six (6) months in any twelve (12) month period and that renders Executive unable to perform the essential functions required under the Agreement. Such determination shall be made by written certification ("Certificate") of Executive's Disability by a physician jointly selected by the Company and Executive; provided that if the Company and Executive cannot reach agreement on appointing the physician, the Certification shall be determined by a panel of physicians consisting of one physician selected by the Company, one physician selected by Executive and a third physician jointly selected by those two physicians.