Niklaus Wirth. Type Extensions. ACM Transactions on Programming Languages and Systems, 10(2):204-214, 1988. [doi]
@article{Wirth88:0,
title = {Type Extensions},
author = {Niklaus Wirth},
year = {1988},
doi = {10.1145/42190.46167},
url = {http://doi.acm.org/10.1145/42190.46167},
researchr = {https://researchr.org/publication/Wirth88%3A0},
cites = {0},
citedby = {0},
journal = {ACM Transactions on Programming Languages and Systems},
volume = {10},
number = {2},
pages = {204-214},
}