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5 Conclusions

The main results of this work may be summarized as follows:
1. A sample of 61 Mkn galaxies detected in the CO(1-0) line was compiled for investigation of the star formation activity. These galaxies were selected from the complete sample of Markarian objects detected by IRAS. The HI, $\element{H}_{2}$, optical and radio continuum data available from the literature are presented for 61 galaxies.
2. The HI and CO line widths are well correlated. Although the HI line width for interacting objects is slightly larger than that for isolated galaxies, it is proposed that interaction has little influence on the HI line broadening in Markarian galaxies. The galaxy interaction has no influence on the CO line broadening.
3. It was suggested that the rapidly rotating nuclear disk in a galaxy could lead to a CO line width greater than the HI line width.
4. The HI and $\element{H}_{2}$ gas phases are well correlated with both the past and present star formation indicators such as the blue, FIR and radio continuum surface brightness. However, the molecular phase is related to these indicators more strongly than to the atomic phase. The gas phases are also correlated. In some relations, the isolated and interacting galaxies have different behaviour (see Table 3).
5. In general, the galaxies with UV-excess (Markarian galaxies) do not differ in their star formation properties from the non-UV galaxies.

Acknowledgements
I gratefully thank J.-M. Martin, for his consent to use some unpublished results of observations. It is a great pleasure to thank A. Nikoghossian for the valuable comments. I wish to thank the anonymous referee who helped improve the manuscript. This research has made use of the NASA-IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, Caltech, under contract with the National Aeronautics and Space Administration (USA); the Lyon-Meudon Extragalactic Database (LEDA), supplied by the LEDA team at CRAL-Observatoire de Lyon (France).

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