@Misc{Wiki,
 howpublished = {\url{http://en.wikipedia.org/wiki/Physa_fontinalis}}
} 

@Book{Kooy2010,
 author = {Kooijman, S.A.L.M.},
 year = {2010},
 title  = {Dynamic Energy Budget theory for metabolic organisation},
 publisher = {Cambridge Univ. Press, Cambridge},
 pages = {Table 4.2 (page 150), 8.1 (page 300)},
 howpublished = {\url{../../../bib/Kooy2010.html}}
} 

@Article{Wit1955,
 author = {W.F. de Wit},
 year = {1955},
 title = {The life cycle and some other biological details of the fresh-water snail \emph{Physa fontinalis} ({L}.)},
 journal = {Basteria},
 volume = {19(2/3)},
 pages = {35-44}
} 

@Article{Wit1955a,
 author = {W.F. de Wit},
 year = {1955},
 title = {The life cycle and some other biological details of the fresh-water snail \emph{Physa fontinalis} ({L}.)},
 journal = {Basteria},
 volume = {19(4)},
 pages = {45-76}
}