A reference can be to a use.Logical formLearned from26 sentences. Reference can be to music.Logical formLearned from26 sentences. References can be philosophical.Logical formLearned from26 sentences. Some references can be to religion.Logical formLearned from26 sentences. Reference can be to a model.Logical formLearned from26 sentences. References can be to historical events.Logical formLearned from26 sentences. A reference can be used.Logical formLearned from26 sentences. Reference can be to others.Logical formLearned from26 sentences. Reference can be to a planet.Logical formLearned from26 sentences. A reference can be to persons.Logical formLearned from26 sentences. (Reference tools) can be electronic.Logical formLearned from26 sentences. A person may add a reference.Logical formLearned from26 sentences. An end may pertain-to a reference.Logical formLearned from26 sentences. A reference can be to an element.Logical formLearned from26 sentences. (Reference materials) can be electronic.Logical formLearned from26 sentences.