It prints a message to STDOUT saying that it doesn't match the first paper. Why not? That one is in the Anthology and should return the following bibtex:
@inproceedings{mueller-schuetze-2011-improved,
title = "Improved Modeling of Out-Of-Vocabulary Words Using Morphological Classes",
author = "Mueller, Thomas and
Schuetze, Hinrich",
booktitle = "Proceedings of the 49th Annual Meeting of the Association for Computational Linguistics: Human Language Technologies",
month = jun,
year = "2011",
address = "Portland, Oregon, USA",
publisher = "Association for Computational Linguistics",
url = "https://www.aclweb.org/anthology/P11-2092",
pages = "524--528",
}