Error in getting a URL into my .bib file using Texworks

When trying to get my .bib file into my .tex i get this error message.

``````You're missing a field part---line 52 of file Bib.bib
:  howpublished =
I'm skipping whatever remains of this entry
``````

In my .tex file i start my bibliogrphy as follows:

``````\bibliographystyle{plainnat}
\bibliography{Bib}
``````

My .bib file for this url with the error message is as follows:

``````@misc{10,
author = "Anupam Gupta",
title = "Linear Programming Duality",
}
``````

My preamble is large but it is as follow:

``````\usepackage{graphicx} % For including graphics (via \includegraphics).
\usepackage{amsmath}  % Improves typographic quality of mathematical output.
\usepackage{amsfonts} % For mathematical fonts.
\usepackage{multirow}
\usepackage{dsfont}
\usepackage{amsthm} % Needed to typeset theorem environments.
\usepackage[affil-it]{authblk} % Needed for author and affiliation.
\usepackage{amsopn} % Allows the declaration of new mathematical operators.
\usepackage{amssymb} % Extended set of mathematical symbols.
\usepackage{mathrsfs} % Raph Smith's mathematical script font.
\usepackage{booktabs} % Improves the typographical quality of tables.
\usepackage{natbib} % Citations and bibliography.
\usepackage{tikz} % Extends the figure generation capabilities of LaTeX.
\usepackage{algorithm} % Necessary for including algorithmic structures.
\usepackage{float} % Allows the creation of own floating environments.
\usepackage{caption} % Allows the customisation of captions.
\usepackage{abstract} % For including abstracts in documents.
\usepackage{listings} % For the inclusion of source code.
\usepackage{color} % Used for colour commands.
\usepackage{pgfplots} %extends tikz functionality
\usepackage{hyperref,lipsum}
\usepackage{url}
\usepackage[english]{babel}
\usepackage[parfill]{parskip}
\usepackage[scale=0.8,vmarginratio={1:2},heightrounded]{geometry}
\usepackage{mathtools}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric,arrows}
``````
• I'm just guessing, but the `howpublished` entry is delimited by two single quotes (`''`). But usually the delimiter is one double quote (`"`). Change to double quotes to see what happens. – Phelype Oleinik Feb 15 '18 at 15:18
• Welcome to TeX.SX! You can also use braces instead of `"` (which TeXworks has the bad habit to change into `''`). – egreg Feb 15 '18 at 15:20
• @PhelypeOleinik - you should post your comment as an answer. :-) – Mico Feb 15 '18 at 15:20
• Off-topic: The `hyperref` package should be loaded last. Also: no need to load the `tikz` package -- or any other package... _ twice. – Mico Feb 15 '18 at 15:22
• @Mico Done :). I'm not at the computer, so I wasn't sure. – Phelype Oleinik Feb 15 '18 at 15:27

The problem is the delimiter of the `howpublished` field.

The valid separators for bibtex files are double quotes (`" "`) and curly braces (`{ }`).

The file you posted is using a pair of single quotes (`'' ''`) and this is breaking bibtex.

``````@misc{10,
author = "Anupam Gupta",
title = "Linear Programming Duality",
}
``````

or

``````@misc{10,
author = "Anupam Gupta",
title = "Linear Programming Duality",