For the time being, these two sorts of citations give different information, have different utilities.
No, it is clearly and everyone agrees, not acceptable practice to cite only the URL. You can even state in the publication that you have a copy of the exact PDF which corresponds with your reference.
Streamline and simplify your writing process by using an online or collaborative authoring tool.
Or is it compulsory to give proper authors, title, year of publication, etc... Example: Data mining is the process of analyzing large data sets in order to discover hidden patterns within these data sets. Stock market prices do not follow random walk. 
id=5FIEAwyn9ao C  No, it's not OK to cite URLs because firstly, you are citing ONLY the URL!
This is the same reason why citations should still include page numbers, even though a quick Google search on the title and authors almost always finds the paper.
On the other hand, books go out of print, library subscriptions lapse, some conference proceedings are only distributed online, some papers are still preprints, and sometimes the source in question is a blog, a usenet post, a source code repository, or a Stack Exchange question.
For example, I used a URL resource from the libary of congress because it was unpublished historical (circa 1890AD) blueprints scanned into their library.
give the more traditional reference information as well.
Whether you need a solution for importing reference libraries, real-time collaboration with co-authors, or importing and exporting in different formats and markup language, authoring tools help manage the writing process so you can focus on creating impactful content. Access the Wiley Author Learning and Training Channel to discover expert advice on a broad range of publishing topics, for example: How to get published; How to write for scientific publications; Grant funding tips; Understand the peer review process; Improve article/publication discoverability; Ethics in publishing; Open Access; Time management skills.
A critical analysis of an article, a book, essay writing or another work is aimed to evaluate its effectiveness and to analyze it, making an argument.