@InCollection{nel,

author = {Till Mossakowski and Joseph Goguen and R\u{a}zvan Diaconescu and Andrzej Tarlecki},

title = {What is a Logic?},

booktitle = {Logica Universalis},

pages = {113--133},

publisher = {Birkh\"{a}user},

year = 2005,

editor = {Jean-Yves B\'{e}ziau}

}