The PDF file you selected should load here if your Web browser has a PDF reader plug-in installed (for example, a recent version of Adobe Acrobat Reader).

If you would like more information about how to print, save, and work with PDFs, Highwire Press provides a helpful Frequently Asked Questions about PDFs.

Alternatively, you can download the PDF file directly to your computer, from where it can be opened using a PDF reader. To download the PDF, click the Download link above.

Fullscreen Fullscreen Off

Refbacks

  • There are currently no refbacks.


Copyright (c) 2018 Vyara Slavyanska

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

ISSN 1314-9113 (print), ISSN 2535-0609 (on-line)

For registration, please contact: science@uard.bg

Because of security reasons the registration is made by the editor.