<!-- NLM Serials DTD
                  
       Comments and suggestions are welcome.

    **This is the 2018 DTD in use as of January 15,2018.
    This DTD was written by the National Library of Medicine 
    for internal and external use.
                
        * = 0 or more occurrences (optional element, repeatable)
        ? = 0 or 1 occurrences (optional element, at most 1)
        + = 1 or more occurrences (required element, repeatable)
        | = choice, one or the other but not both 
        no symbol = required element

-->
<!-- ================================================================= -->
<!--   Revision Notes Section 

  The following changes were made from the nlmserials_170101.dtd. This
  DTD is backward-compatible with nlmserials_170101.dtd.
  
       a.  Changed nlmserials_170101.dtd to nlmserials_180101.dtd. 
     
-->
<!-- ================================================================= -->
<!ELEMENT SerialsSet (Serial+)>
<!ELEMENT Serial (NlmUniqueID, Title, MedlineTA?, PublicationInfo?, ISSN*, 
          ISSNLinking?, ISOAbbreviation?, Language*, AcidFreeYN?,
          Coden?, TitleContinuationYN?, GeneralNote*, TitleRelated*,
          CurrentFormatStatus?, MinorTitleChangeYN?, IndexingStartDate?,
          ProcessingCode?, IndexingHistoryList?, 
          CurrentlyIndexedYN?, CurrentlyIndexedForSubset*, 
          IndexOnlineYN?, IndexingSubset?, IndexingSelectedURL?,
          ReportedMedlineYN, BroadJournalHeadingList?, 
          MeshHeadingList?, CrossReferenceList?, SortSerialName,
          IlsCreatedTimestamp?, IlsUpdatedTimestamp?, 
          DeletedTimestamp?,
          MedlineDataUpdatedTimestamp?,
          SEFCreatedTimestamp?, SEFUpdatedTimestamp?)>
<!ATTLIST Serial
	DataCreationMethod (P | K | O) #IMPLIED
        MedPrintYN (Y | N) #IMPLIED
	PMC (Yes | Forthcoming | InProcess | Inactive) #IMPLIED
	Status (NLMCollection | NotNLMCollection) #REQUIRED
>
<!ELEMENT AcidFreeYN (#PCDATA)>
<!ELEMENT BroadJournalHeading (#PCDATA)>
<!ELEMENT BroadJournalHeadingList (BroadJournalHeading+)>
<!ELEMENT Coden (#PCDATA)>
<!ELEMENT Country (#PCDATA)>
<!ELEMENT Coverage (#PCDATA)>
<!ELEMENT CoverageNote (#PCDATA)>
<!ELEMENT CrossReference (XrTitle)>
<!ATTLIST CrossReference
	XrType (A | X | S) #REQUIRED
>
<!ELEMENT CrossReferenceList (CrossReference+)>
<!ELEMENT CurrentFormatStatus (#PCDATA)>
<!ELEMENT CurrentlyIndexedForSubset (#PCDATA)>
<!ATTLIST CurrentlyIndexedForSubset
	CurrentSubset (AIM | D | E | H | IM | K | N | Q | QIS | S | T | X) #REQUIRED
	CurrentIndexingTreatment (Full | Selective | Unknown) #REQUIRED
>
<!ELEMENT CurrentlyIndexedYN (#PCDATA)>
<!ELEMENT DateOfAction (Year, Month, Day, (Hour, (Minute, Second?)?)?)>
<!ELEMENT DatesOfSerialPublication (#PCDATA)>
<!ELEMENT Day (#PCDATA)>
<!ELEMENT DeletedTimestamp (Year, Month, Day, (Hour, (Minute, Second?)?)?)>
<!ELEMENT DescriptorName (#PCDATA)>
<!ATTLIST DescriptorName
	MajorTopicYN (Y | N) "N"
        Type (Geographic) #IMPLIED
>
<!ELEMENT Frequency (#PCDATA)>
<!ATTLIST Frequency
	FrequencyType (Current | Former) "Current"
>
<!ELEMENT GeneralNote (#PCDATA)>
<!ATTLIST GeneralNote
    NoteType (LinkComplexNote) #IMPLIED
>
<!ELEMENT Hour (#PCDATA)>
<!ELEMENT IlsCreatedTimestamp (Year, Month, Day, (Hour, (Minute, Second?)?)?)>
<!ELEMENT IlsUpdatedTimestamp (Year, Month, Day, (Hour, (Minute, Second?)?)?)>
<!ELEMENT IndexOnlineYN (#PCDATA)>
<!ELEMENT IndexingHistory (DateOfAction, Coverage?, CoverageNote?)>
<!ATTLIST IndexingHistory
	CitationSubset (AIM | B | C | D | E | F | H | IM | J | K | N | 
                        OM | P | Q | QIS | R | S | T | X) #REQUIRED
	IndexingTreatment (Unknown | Full | Selective | ReferencedIn |
                           ReferencedInNoDetails) #IMPLIED
	IndexingStatus (Ceased-publication | Continued-by-another-title | 
                        Currently-indexed | Deselected) #IMPLIED
>
<!ELEMENT IndexingHistoryList (IndexingHistory+)>
<!ELEMENT IndexingSelectedURL (#PCDATA)>
<!ELEMENT IndexingStartDate (#PCDATA)>
<!ELEMENT IndexingSubset (#PCDATA)>
<!ELEMENT ISOAbbreviation (#PCDATA)>
<!ELEMENT ISSN  (#PCDATA) >
<!ATTLIST ISSN 
            CreatedTimestamp     CDATA   #IMPLIED
            UpdatedTimestamp    CDATA   #IMPLIED
            IssnType (Electronic | Print | Undetermined) #REQUIRED
>
<!ELEMENT ISSNLinking (#PCDATA)>
<!ELEMENT Language (#PCDATA)>
<!ATTLIST Language
	LangType (Primary | Summary) #REQUIRED
>
<!--  NOTE:  The use of "Medline" in the MedlineTA element name does not mean the data
             represents a MEDLINE-selected journal.  -->
<!ELEMENT MedlineTA (#PCDATA)>
<!ELEMENT MedlineDataUpdatedTimestamp (Year, Month, Day, (Hour, (Minute, Second?)?)?)>
<!ELEMENT MeshHeading (DescriptorName, QualifierName*)>
<!ELEMENT MeshHeadingList (MeshHeading+)>
<!ELEMENT MinorTitleChangeYN (#PCDATA)>
<!ELEMENT Minute (#PCDATA)>
<!ELEMENT Month (#PCDATA)>
<!ELEMENT NlmUniqueID (#PCDATA)>
<!ELEMENT Place (#PCDATA)>
<!ELEMENT ProcessingCode (#PCDATA)>
<!ELEMENT PublicationEndYear (#PCDATA)>
<!ELEMENT PublicationFirstYear (#PCDATA)>
<!ELEMENT PublicationInfo (Country?, Place*, Publisher*, PublicationFirstYear?, 
                           PublicationEndYear?, Frequency*)>
<!ELEMENT Publisher (#PCDATA)>
<!ELEMENT QualifierName (#PCDATA)>
<!ATTLIST QualifierName
	MajorTopicYN (Y | N) "N"
>
<!ELEMENT RecordID (#PCDATA)>
<!ATTLIST RecordID
    Source (NLM | LC | OCLC) #REQUIRED
>
<!ELEMENT ReportedMedlineYN (#PCDATA)>
<!ELEMENT Second (#PCDATA)>
<!ELEMENT SEFCreatedTimestamp (Year, Month, Day, (Hour, (Minute, Second?)?)?)>
<!ELEMENT SEFUpdatedTimestamp (Year, Month, Day, (Hour, (Minute, Second?)?)?)>
<!ELEMENT SortSerialName (#PCDATA)>
<!ELEMENT Title (#PCDATA)>
<!ELEMENT TitleContinuationYN (#PCDATA)>
<!ELEMENT TitleRelated (Title, RecordID*,ISSN?)>
<!ATTLIST TitleRelated
	TitleType (Absorbed | AbsorbedBy | AbsorbedInPart | AbsorbedInPartBy | 
                   Analytic | MergedTo | MergerOf | Other | Preceding | PrecedingInPart | 
                   Related | Reversion | Series | SeriesAuthority | SplitFrom | SplitTo | Succeeding |
                   SucceedingInPart | SupersededBy | SupersededInPartBy | 
                   Supersedes | SupersedesInPart | Translated | Undetermined) "Undetermined"
>
<!ELEMENT XrTitle (#PCDATA)>
<!ELEMENT Year (#PCDATA)>