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.)
Legenda: Type L=leaf, S=specializable, A=abstract, D=deprecated. NullFlavors to appear
in @nullFlavor attribute instead of @code. NullFlavor OTH (other) suggests text in
originalText.