Here are citations for common citation formats: 

APA:
Lussi, R., & Kim, S.. (2015). Under and over exposed image dataset by iaslab. https://iaslab.org/download#under_over_exposed_db.

MLA:
Lussi, Rolf et al. "Under and over exposed image dataset by iaslab." https://iaslab.org/download#under_over_exposed_db. (2015).

Chicago:
Lussi, Rolf, and Suah, Kim. "Under and over exposed image dataset by iaslab." https://iaslab.org/download#under_over_exposed_db. (2015).

Harvard:
Lussi, R., and Kim, S.. (2015). Under and over exposed image dataset by iaslab. https://iaslab.org/download#under_over_exposed_db.

Vancouver:
Lussi, R, Kim, S. Under and over exposed image dataset by iaslab. https://iaslab.org/download#under_over_exposed_db.

bibtex: 
@misc{SK_iaslab_under_and_over_exposed_db,
author = {Lussi, Rolf and Kim, Suah},
title = {Under and over exposed image dataset by iaslab},
year = 2015,
howpublished = {\url{https://iaslab.org/download#under_over_exposed_db}},
publisher={iaslab},
}