Reference books can be an excellent starting point for locating quick, background information and developing an understanding of a topic.
Lots of online reference sources are available via the library catalogue and Discovery.
Encyclopedia of language and education by 
Encyclopedia of bilingual education
The concise Oxford English dictionary by 
Macquarie Dictionary and Thesaurus
Encyclopedia of linguistics
Compendium of the world's languages
Macquarie book of slang
Teaching English language learners in career and technical education programs
How to Reach and Teach English Language Learners by 
The Reflective Teacher Educator in TESOL by 
Teaching English language learners through technology
Techniques and Principles in Language Teaching by 
Teaching mathematics to English language learners
Teaching social studies to English language learners
Teaching English language learners : content and language in middle and secondary mainstream classrooms