@inproceedings {4209,
	title = {On the Relative Age of Spam and Ham Training Samples for Email Filtering},
	booktitle = {International Conference on Research and Development in Information Retrieval (SIGIR)},
	year = {2009},
	doi = {10.1145/1571941.1572107},
	author = {Gordon Cormack and Jos{\'e}-Marcio Martins da Cruz}
}
