@InCollection{LU2008b,
	author = 	{Pawe{\l} {\L}upkowski and Mariusz Urba\'{n}ski},
	title = 	{Sem\textsc{captcha} -- user-friendly alternative for OCR-based \textsc{captcha} systems},
	booktitle = 	{Speech and Language Technology},
	pages = 	{289--278},
	publisher = 	{Polish Phonetics Association},
	year = 		{2008},
	editor = 	{Gra\.{z}yna Demenko and Krzysztof Jassem and Stanis{\l}aw Szpakowicz},
	volume = 	{11},
	address = 	{Pozna\'{n}},
}