An eLML lesson always starts with either the mandatory introduction (element entry) or a concise listing of the lesson’s learning objectives (element goals). The unit elements, described below, contain the actual content of a lesson. Following the units a lesson can have a summary and/or up to five self-assessments followed by an optional further reading and glossary section to list important resources and to describe terms used within the lesson. The XML Schema ensures that all glossary terms used in a lesson are defined in the glossary. The Harvard Referencing System or the APA style can be used for the bibliography. All citations, references, further readings etc., must be listed within the bibliography section, otherwise the XML parser issues an error and the lesson is not valid.