References
- Valníček , B. , Letfus , V. Blaha , M. 1959 . Bull. Astron. Inst. Czech. , 10 : 149
- Kotrč , P. , Heinzel , P. and Knížek , M. 1993 . JOSO Annual Report Edited by: Alvensleben , A. V. 114
- Kotrč , P. 1997 . Hvar Obs. Bull. , 21 : 97
- Klvaňa , M. , Sobotka , M. Kotrč , P. 2001 . Astron. Nachr. , 322 : 371
- Kotrč , P. and Kschioneck , K. Proceedings of the International Solar Cycle Studies 2003 Symposium: SOLAR VARIABILITY AS AN INPUT TO THE EARTH'S ENVIRONMEN . June . pp. 717 – 722 . Tatranska Lomnica, , Slovak Republic ESA SP-535
- Kotrč , P. , Heinzel , P. Kononovich , E. V. Proceedings of the 144th Colloquium of the International Astronomical Union . September . pp. 361 Tatranská Lomnica, , Slovakia
- Karlický , M. , Kotrč , P. and Kupryakov , Yu. 2000 . Sol. Phys. , 199 : 145
- Karlický , M. , Kotrč , P. and Kupryakov , Yu. 2002 . Sol. Phys. , 211 : 231