Index Identification                     ---- Head sorting method
	l Head: most important word syntactically and semantically. ¡ Filter is the head of coffee filter, oil filter, etc l Simplex NPs (SNP) are identified instead of Complex NP (CNP) ¡ “A form” and “cancer causing asbestos” are two SNP ¡ “A form of cancer causing asbestos” is a CNP. l NPs are sorted by head in terms of their significances (frequency)