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2. Agustin Delgado etal 2011. ZXing (Zebra Crossing) barcode scanning library for Java Android. https://github.com/zxing/zxing Agustin Delgado et al. 2011. ZXing (Zebra Crossing) barcode scanning library for Java Android. https://github.com/zxing/zxing
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4. COPSS: An Efficient Content Oriented Publish/Subscribe System