Thank you. I haven't originally found the first question and the second seemed to specialized for me. In particular I wasn't able to tell, whether the question intended was: ''We know that roots of arbitrary polynomials are expressible in terms of some class of special functions. Can it be also done with Bring radicals?'' or rather ''We do not know much about finding roots of arbitrary polynomials. Are Bring radicals a solution to this problem?''

Great! Thank you for the book reference and link. I only browsed through MO and tried to google it. As a response to the same question posted in MS one of the comments to the following question has been linked: scicomp.stackexchange.com/questions/1864/…