[Tex/LaTex] I get a warning that the entry type of one the cites “isn’t style-file defined”

Question

(no line number):
This is BibTeX, Version 0.99d (TeX Live 2015/Debian)
Capacity: max_strings=35307, hash_size=35307, hash_prime=30011
The top-level auxiliary file: Semester.aux
The style file: alpha.bst
Database file #1: bibio.bib.bib
Warning--entry type for "Teknologikatalog" isn't style-file defined
--line 2 of file bibio.bib.bib
I was expecting a `,' or a `}'---line 9 of file bibio.bib.bib
 : 

This is what i wrote in my bibliography

@misc{Teknologikatalog,
    Author = "Teknologikatalog",
    Title = "Energistyrelsen",
    howpublished = {\url{https://ens.dk/service/fremskrivninger-analyser-modeller/teknologikataloger},
    {Sidst set 09/11-2016}}

Answer 1

Some suggestions:

• Do provide a year field. That way, you'll get properly-formed citation call-out labels.

• Using the entry type @online does no harm, but also little good, since it (a) isn't defined in the alpha bibliography style and (b) thus automatically gets treated as an entry of type @misc, which is the "catch-all" or "default" entry type. The use of the entry type @online, by the way, is the trigger for the warning message

  Warning--entry type for "Teknologikatalog" isn't style-file defined
  

• I'd use the note field instead of the howpublished field for the URL and the date the website was last visited. That way, the year-related information will come before the URL.

• Don't include the ".bib" extension in the argument of \bibliography. I.e., write \bibliography{biblio}, not \bibliography{biblio.bib}.

An MWE:

\RequirePackage{filecontents}
\begin{filecontents}{biblio.bib}
@online{Teknologikatalog,
    Author = "Teknologikatalog",
    Title  = "Energistyrelsen",
    note   = {\url{https://ens.dk/service/fremskrivninger-analyser-modeller/teknologikataloger}, Sidst set 09/11/2016},
    year   = 2016,
}
\end{filecontents}

\documentclass{article}
\usepackage[danish]{babel} % just a hunch...
\usepackage[hyphens]{url}
\bibliographystyle{alpha}

\begin{document}
\cite{Teknologikatalog}
\bibliography{biblio} 
\end{document}