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	VALIDITY
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<!--  Validity data -->

<!-- Contacts: WIPO: Patrick FIEVET (patrick.fievet@wipo.int).-->

<!ELEMENT ipcr-validity-list  (subclass-list+) >

<!ELEMENT subclass-list  (subclass-description,ipcr-symbol+) >

<!ELEMENT subclass-description  (section,class,subclass) >

<!ELEMENT ipcr-symbol  (main-group?,subgroup?) >

<!ATTLIST ipcr-symbol
               classification-level (P | C | O | A | S)   #REQUIRED
               entry-type (K | I | D )   #REQUIRED
               validity-date-from  CDATA    #REQUIRED
               validity-date-to  CDATA    #IMPLIED
               core-predecessor  CDATA    #IMPLIED  >

<!-- ipcr-symbol values
	classification-level:
		P=Pre reform (i.e prior to IPC reform)
		C=Core level(i.e for BOTH Core and Advanced Level classification)
		O=valid for Core level symbol, Obsolete for the Advanced level  (i.e for Core level symbols no longer valid in the Advanced level)
		A=Advanced level (i.e Advanced level classification ONLY)
		S=Subclass level (i.e Subclass level classification ONLY)

	entry-type
		K=classification symbol
		I=indexing symbol
		D=Double purpose symbol (Pre reform only)

	validity-date-from and validity-date-to
		They are in YYYYMMDD format
	For Pre-reform IPC symbols the correspondence between editions and dates is as follows:
		edition 1: from 19680901 to 19740630
		edition 2: from 19740701 to 19791231
		edition 3: from 19800101 to 19841231
		edition 4: from 19850101 to 19891231
		edition 5: from 19900101 to 19941231
		edition 6: from 19950101 to 19991231
		edition 7: from 20000101 to 20051231
		edition 8: from 20060101 to
-->

<!ELEMENT section  (#PCDATA) >

<!ELEMENT class  (#PCDATA) >

<!ELEMENT subclass  (#PCDATA) >

<!ELEMENT main-group  (#PCDATA) >

<!ELEMENT subgroup  (#PCDATA) >