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Attack Warning System : Portland Map tentative location for sirens | M/1637 | 12/31/1952 | ||
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Attack Warning System : Portland Map showing location of sirens | M/1638 | 12/31/1952 at 9:14:02 AM | ||
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Attack Warning System : Portland Map showing location of the sirens and there previously planned location | M/1639 | 12/31/1952 | ||
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Blueprint Plan : Air raid siren platform, American Bank Building | M/1640 | 07/10/1953 |