**6. Acknowledgment**

Thank you to the researches from OrbFit Consortium working in four research laboratories: http://adams.dm.unipi.it/~orbmaint/orbfit/OrbFit/doc/help.html#authors for theirs free software and source code.

Thank you very much for Andrea Milani and Geny Sansaturio for discussions during MACE 2006 and for the help through e-mails.

I also thank Aldo Vitagliano for his discussion about Solex during Mace 2006.

I would like to thank Fabrizio Bernardi for his help in the OrbFit v.4.2.

I would like to thank Grzegorz Sitarski from the Space Research Center, of the Polish Academy of Sciences in Warsaw for his impact solutions of (99942) Apophis and (144898) 2004 VD17 and profound and fruitful help.

I am also grateful for the suggestions given by Leonard Kornos.

## **7. References**

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Vitagliano, A. and Stoss, R. (2006). *Astron. Astrophys.* 455, L29

Wlodarczyk, I. (2001). *Acta Astron.* 51, 357

Yeomans, D.K., Ostro, S.J., Chodas, P.W. (1987). *Astron. J.* 94, 189
