@article{Harper_1992,
    doi = {10.1016/0747-7171(92)90026-z},
    url = {https://doi.org/10.1016%2F0747-7171%2892%2990026-z},
    year = {1992},
    month = {jul},
    publisher = {Elsevier {BV}},
    volume = {14},
    number = {1},
    pages = {71--84},
    author = {Robert Harper},
    title = {Constructing type systems over an operational semantics},
    journal = {Journal of Symbolic Computation}
}

@article{Harper_1992, doi = {10.1016/0747-7171(92)90026-z}, url = {https://doi.org/10.1016%2F0747-7171%2892%2990026-z}, year = {1992}, month = {jul}, publisher = {Elsevier {BV}}, volume = {14}, number = {1}, pages = {71--84}, author = {Robert Harper}, title = {Constructing type systems over an operational semantics}, journal = {Journal of Symbolic Computation} }