@article {10103,
	title = {A non-invasive method of tracing spiral tips},
	journal = {Chinese Physics Letters},
	year = {2001},
	pages = {834-836},
	doi = {10.1088/0256-307X/18/6/341},
	author = {Kai Wang and Xiao-Ming Mao and Qi Ou-Yang}
}
