@ARTICLE{
author={Napijalo Veljko M},
year={2012},
title={Coupled Line 180 degrees Hybrids With Lange Couplers},
journal={IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES},
volume={60},
number={12},
pages={3674-3682},
document_type={Article},
} 

@ARTICLE{
author={Djordjevic Antonije R,Napijalo Veljko M,Olcan Dragan I,Zajic Alenka G},
year={2012},
title={Wideband multilayer directional coupler with tight coupling and high directivity},
journal={MICROWAVE AND OPTICAL TECHNOLOGY LETTERS},
volume={54},
number={10},
pages={2261-2267},
document_type={Article},
}