The test sets ubo10, ubo20, ubo50, and ubo100 were created by Klaus Neumann and
Christoph Schwindt (see Neumann, K., Schwindt, C.: Project scheduling with
inventory constraints. Mathematical Methods of Operations Research 56(3),
513–533 (2002) for your reference).

The test set ubo200 were created by Andreas Schutt and Peter J. Stuckey (see
Schutt, A., Stuckey, P.J.: Explaining Producer/Consumer Constraints.
International Conference on Principles and Practice of Constraint Programming -
CP 2016. LNCS, vol. 9892, pp. 438-454. Springer International Publishing (2016)
for your reference).
