add additional reference for 8div* instances

@incollection{ubt_eref40887,

          author = {Daniel Heinlein and Thomas Honold and Michael Kiermaier and Sascha Kurz and Alfred Wassermann},

       booktitle = {The Tenth International Workshop on Coding and Cryptography 2017 : WCC Proceedings},

         address = {Saint-Petersburg},

           month = {September},

           title = {Projective divisible binary codes},

            year = {2017},

             url = {https://eref.uni-bayreuth.de/40887/},

        keywords = {divisible codes; projective codes; partial spreads}

}

@article{heinlein2017classifying,

@article{heinlein2017classifying,

  title   =  {Classifying optimal binary subspace codes of length 8, constant dimension 4 and minimum distance 6},

  title   =  {Classifying optimal binary subspace codes of length 8, constant dimension 4 and minimum distance 6},

  author  =  {Heinlein, Daniel and Honold, Thomas and Kiermaier, Michael and Kurz, Sascha and Wassermann, Alfred},

  author  =  {Heinlein, Daniel and Honold, Thomas and Kiermaier, Michael and Kurz, Sascha and Wassermann, Alfred},

  journal =  {Designs, Codes and Cryptography},

  journal =  {Designs, Codes and Cryptography},

  note    =  {arXiv preprint arXiv:1711.06624},

  note    =  {arXiv preprint arXiv:1711.06624},

  year    =  {to appear},

  year    =  {to appear},

  doi     =  {10.1007/s10623-018-0544-8},

  doi     =  {10.1007/s10623-018-0544-8}

}

}

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