@article{DIA_1990__24__7_0,
     author = {Gray, John W.},
     title = {Executable specifications for data-type constructors},
     journal = {Diagrammes},
     pages = {7--31},
     publisher = {Universit\'e Paris 7, Unit\'e d'enseignement et de recherche de math\'ematiques},
     volume = {24},
     year = {1990},
     zbl = {0792.68101},
     language = {en},
     url = {http://www.numdam.org/item/DIA_1990__24__7_0/}
}