Preface to the English edition
Foundations of the Theory of Groupoids and Groups, GDML_Books, (1974), p. [5] / Harvested from
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@inbook{401536,
     title = {Preface to the English edition},
     booktitle = {Foundations of the Theory of Groupoids and Groups},
     series = {GDML\_Books},
     publisher = {VEB Deutscher Verlag der Wissenschaften},
     address = {Berlin},
     year = {1974},
     pages = {[5]-[5]},
     url = {http://dml.mathdoc.fr/item/401536}
}

 (éd.). Preface to the English edition, dans Foundations of the Theory of Groupoids and Groups, GDML_Books,  (1974), p. [5]. http://gdmltest.u-ga.fr/item/401536/