Lettington, A. Optical Systems for Space and Defence. SPIE Digital Library.
Citazione stile Chigago Style (17a edizione)Lettington, Alan. Optical Systems for Space and Defence. SPIE Digital Library.
Citatione MLA (9a ed.)Lettington, Alan. Optical Systems for Space and Defence. SPIE Digital Library.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.