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Abstract (A&A 423 p.415)

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References of  A&A 423 p. 415

• Aharonian, F., Akhperjanian, A., Beilicke, M., et al. 2002, A&A, 393, L37 [EDP Sciences] [NASA ADS]
• Akerlof, C. W., Cawley, M. F., Chantell, M., et al. 1991, ApJ, 377, L97 [NASA ADS]
• Atkins, R., Benbow, W., Berley, D., et al. 2004, ApJ, 608, 680 [NASA ADS]
• Bednarek, W. 2003, MNRAS, 345, 847 [NASA ADS]
• Butt, Y. M., Benaglia, P., Combi, J. A., et al. 2003, ApJ, 597, 494 [NASA ADS]
• Cawley, M. F., Fegan, D. J., Harris, K., et al. 1990, Exp. Astron., 1, 173 [NASA ADS]
• Cui, S. W., & Yan, C. T. (on behalf of the Tibet AS Gamma Collaboration) 2003, Proc. 28th ICRC (Tsukuba), 4, 2315
• Finley, J. P. 2003, BAAS, A&AS 203rd Meet. (Atlanta, 2004), 35, 1216
• Fomin, V. 2004, private communication
• Hartman, R. C., Bertsch, D. L., Bloom, S. D., et al. 1999, ApJS, 123, 79 [NASA ADS]
• Horan, D., & Weekes, T. C. 2004, New Astron. Rev., 48, 527 [NASA ADS]
• Lamb, R. C., & Macomb, D. 1997, ApJ, 488, 872 [NASA ADS]
• Lang, M. J., et al. 1991, Proc. 22nd ICRC (Dublin), 1, 204 [NASA ADS]
• Lessard, R. W., Buckley, J. H., Connaughton, V., & Le Bohec, S. 2001, Astropart. Phys., 15, 1 [NASA ADS]
• Li, T. P., & Ma, Y. Q. 1983, ApJ, 272, 317 [NASA ADS]
• Mukherjee, R., Halpern, J. P., Gotthelf, E. V., Eracleous, M., & Mirabal, N. 2003, ApJ, 589, 487 [NASA ADS]
• Neshpor, Yu. I., Kalekin, O. R., Stepanian, A. A., et al. 1995, Proc. 25th ICRC (Rome), 2, 385
• O'Flaherty, K. S., Cawley, M. F., Fegan, D. J., et al. 1992, ApJ, 396, 674 [NASA ADS]
• Punch, M., Akerlof, C. W., Cawley, M. F., et al. 1991, Proc. 22nd ICRC (Dublin), 1, 464 [NASA ADS]
• Reynolds, P. T., Akerlof, C. W., Cawley, M. F., et al. 1993, ApJ, 404, 206 [NASA ADS]
• Rowell, G., & Horns, D. (for the HEGRA Collaboration) 2003, Proc. 28th ICRC (Tsukuba), 4, 2345
• Torres, D. F., Domingo-Santamaria, E., & Romero, G. E. 2004, ApJ, 601, L75 [NASA ADS]
• Vacanti, G., Cawley, M. F., Colombo, E., et al. 1991, ApJ, 377, 467 [NASA ADS]
• Vladimirsky, B. M., Stepanian, A. A., & Fomin, V. P. 1973, Proc. 13th ICRC (Denver), 1, 456
• Weekes, T. C., Helmken, H., & Horine, E. 1979, Proc 16th ICRC (Kyota) 1, 126

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Abstract (A&A 423 p.415)

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

• If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
• You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
• You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.