@article {liu2011isomorphism,
	title = {Isomorphism check in fractional factorial designs via letter interaction pattern matrix},
	journal = {Journal of Statistical Planning and Inference},
	volume = {141},
	number = {9},
	year = {2011},
	pages = {3055{\textendash}3062},
	publisher = {Elsevier},
	author = {Liu, Yang and Yang, Jian-Feng and Liu, Min-Qian}
}
