@article {36604,
	title = {Bias in progression-free survival analysis due to intermittent assessment of progression},
	journal = {Statistics in Medicine},
	volume = {34},
	year = {2015},
	pages = {3181-3193},
	isbn = {0277-6715},
	author = {Zeng, Leilei and Cook, Richard J and Wen, Lan and Boruvka, Audrey}
}
