1. Phase contrast, a new method for the microscopic observation of transparent objects part II;Zernike;Physica.,1942
2. Phase contrast, a new method for the microscopic observation of transparent objects;Zernike;Physica.,1942
3. Differential phase contrast in scanning optical microscopy;Hamilton;J. Microsc.,1984
4. Generalised phase contrast: Microscopy, manipulation and more;Palima;Contemp. Phys.,2010
5. Spiral phase contrast imaging in microscopy;Fürhapter;Opt. Express.,2005