According to a 2011 review of analytical and computational textbooks in electromagnetism by David Davidson, Julius Stratton 's Electromagnetic Theory remains the classic text in electromagnetism and is still regularly cited. Davidson goes on to point out that Constantine Balanis ' Advanced Engineering Electromagnetics and Roger Harrington 's Time-Harmonic Electromagnetic Fields are standard references at the post-graduate level. Also for advanced undergraduate level, the textbook Fields and Waves in Communication Electronics by Simon Ramo, John Whinnery, and Theodore Van Duzer is considered as standard reference.