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Dr. David Graham of the Veterans Administration O Center in Houston , who has also studied the new drug , said some experts are concerned about the long-term effects of shutting down acid secretion almost completely .
 Work for: David Graham, Veterans Administration O Center; Organization based in: Veterans Administration O Center, Houston
Given options, please tell me the relationships of all the listed entity pairs.Output format is "relation1: word1, word2; relation2: word3, word4". 
Option: Organization based in, Located in, Live in, Work for, Kill 
Text: {0} 
 Entity Pairs:  David Graham, Veterans Administration O Center; Veterans Administration O Center, Houston 
Answer:
 Work for: David Graham, Veterans Administration O Center; Organization based in: Veterans Administration O Center, Houston