Determining how to express a range of dates for the Works/Plays:

• when there is a range of dates on general and volume title pages (*not play t.p.), include all dates, separated by a hyphen, in 260 subfield c:   |c MDCCL-MDCCLI [1750-1751]
• fixed field dates will reflect this range:  DtSt m Dates 1750, 1751
• per LCRI 25.8, Uniform title date will reflect earliest date in the range:  240 10 Plays. |f 1750
• 1750-1751 Works of Shakespear: 

                    http://shakespeare.folger.edu/cgi-bin/Pwebrecon.cgi?BBID=130776

Incorrect dates:

Migrated to http://folgerpedia.folger.edu/MARC_046_Special_Coded_Dates_%28Bibliographic%29 

• imprint dates might be accidentally or deliberately mis-printed (pirated editions)
• OCLC states: If you use field 046 for incorrect dates, enter the type of corrected dates codes in DtSt and the corrected dates in Dates
• formulate 046 with subfields a and c, reflecting the incorrect date:    046  |a x |c 1635
• fixed field date is the correct date:  DtSt s Date 1735
• uniform title reflects correct date: 240 10 Plays. |f 1735
• transcribe date in 260 subfield c, with "i.e. (correct date) in brackets:   |c MDCXXXV [1635 i.e. 1735] 
• note: OCLC does not reflect searchability for the corrected date (the 046 seems to trump the fixed field date)
  
• 1735 Works of Shakespear (Tonson): 

                    http://shakespeare.folger.edu/cgi-bin/Pwebrecon.cgi?BBID=180721

Estimated dates:

Migrated to http://folgerpedia.folger.edu/MARC_046_Special_Coded_Dates_%28Bibliographic%29

• This isn't documented policy yet, but it's being discussed it for art cataloging... instruction comes from Cataloging Cultural Objects
• If there is no publication date, and a date can only be guessed at, use "[ca. <date>]" in the 260:    |c [ca. 1768]
• The fixed fields will use DtSt q, and a 5-year cushion for that 260 date:    DtSt q Dates 1763, 1773
• The uniform title date reflects the 260 date:   240 10 Plays. |f 1768