import element information items (referred to in this specification as
import elements) are element information items in the CellML namespace
with local name equal to import.
Every import element MUST contain an attribute information item in
the namespace http://www.w3.org/1999/xlink, and with local name href.
The value of this attribute SHALL be a valid locator href, as defined
in section 5.4
of the XLink specification.
The href attribute SHALL be treated according to the XLink specification, by applying
the rules for simple-type elements. When describing an import element
or one of its children, the phrase “imported CellML infoset” SHALL
refer to the CellML infoset obtained by parsing the XML document
referenced by the href attribute.
Every import element MAY contain zero or more specific information
children, each of which MUST be of one of the following types:
An importunits element; or
An importcomponent element.
The imported CellML infoset SHALL NOT be equivalent to this CellML
infoset. Any CellML infoset imported, directly or indirectly, by the
imported CellML infoset SHALL NOT be equivalent to this CellML infoset.