Citations are widely considered in scientists' evaluation. As such, scientists may be incentivized to inflate their citation counts. While previous literature has examined self-citations and citation cartels, it remains unclear whether scientists can purchase citations. Here, we compile a dataset of ~1.6 million profiles on Google Scholar to examine instances of citation fraud on the platform. We survey faculty at highly-ranked universities, and confirm that Google Scholar is widely used when evaluating scientists. Intrigued by a citation-boosting service that we unravelled during our investigation, we contacted the service while undercover as a fictional author, and managed to purchase 50 citations. These findings provide conclusive evidence that citations can be bought in bulk, and highlight the need to look beyond citation counts.

翻译：引用数量在科学家评价中被广泛采用。因此，科学家可能有动机夸大其引用次数。尽管已有文献探讨了自引和引用联盟，但科学家是否能购买引用仍不明确。本研究收集了谷歌学术上约160万份档案的数据集，以检测该平台上的引用欺诈行为。我们对顶尖大学教职员工的调查证实，谷歌学术在科学家评价中被广泛使用。受调查中发现的一项引用提升服务启发，我们以虚构作者身份暗中联系该服务，并成功购买了50次引用。这些发现提供了引用可批量购买的明确证据，突显了超越引用计数进行考量的必要性。