\startbuffer[mukk]
\startpublication
  [k=fundamentals,
   y=1981,
   t=book]
\title {Fundamentals of Database Systems}
\author {Ramez}[R.]{}{Elmasri}
\author {Shamkant B.}[S.\,B.]{}{Navathe}
\pubyear {2007}
\pubname {Addison Wesley}
\edition {5}
\city {Boston}
\stoppublication

\startpublication
  [k=garden,
   t=misc, % What to use here?
   u=http://wiki.contextgarden.net % What is this line for?
  ]
\title {\ConTeXt-Garden}
\biburl {http://wiki.contextgarden.net}
\stoppublication
\stopbuffer
\savebuffer[mukk][\jobname.bbl]

\setuppublications [alternative=ams]
% \setuppublications [alternative=num] % Look for edition

\starttext
As you can see in \cite[fundamentals] or in \cite[garden].

\placepublications
\stoptext