SUMMARY This article is available only in Slovak without a summary.
Doctoral research
SUMMARY This article is available only in Slovak without a summary.
SUMMARY This article is available only in Slovak without a summary.
SUMMARY The summary of this article is available at the end of the document.
SUMMARY This article is available only in Slovak without a summary.
SUMMARY This article is available only in Slovak without a summary.
SUMMARY The summary of this article is not available.
SUMMARY The summary of this article is not available.
SUMMARY The summary of this article is not available.