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2. Tsunesada Y. et al., [The Telscope Array collaboration], “ICRC2011, Beijing, Jul. 2011” arXiv:1111.2507
3. Apel W.D., et al., “ICRC2011, Beijing, Jul. 2011”, arXiv:1111.5436
4. HEAT – a low energy enhancement of the Pierre Auger Observatory
5. The TA and TALE Experiments