History description 2014-03-26: Lock all vaue sets untouched since 2014-03-26 to trackingId 2014T1_2014_03_26
                           
                           description: 
                           
                           A code specifying whether and how the participant has attested his participation through
                              a signature and or whether such a signature is needed.
                           
                           
                           
                              Examples: A surgical Procedure act object (representing a procedure report) requires a signature
                              of the performing and responsible surgeon, and possibly other participants. (See also:
                              Participation.signatureText.)