Ulla Merz, Roger King. Direct: A Query Facility for Multiple Databases. ACM Trans. Inf. Syst., 12(4):339-359, 1994. [doi]
@article{MerzK94,
title = {Direct: A Query Facility for Multiple Databases},
author = {Ulla Merz and Roger King},
year = {1994},
doi = {10.1145/185462.185472},
url = {http://doi.acm.org/10.1145/185462.185472},
researchr = {https://researchr.org/publication/MerzK94},
cites = {0},
citedby = {0},
journal = {ACM Trans. Inf. Syst.},
volume = {12},
number = {4},
pages = {339-359},
}