@article {martinez07spectralEfficiencyDirectDetection,
	title = {Spectral Efficiency of Optical Direct Detection},
	journal = {J. Opt. Soc. Am. B},
	volume = {24},
	number = {4},
	year = {2007},
	month = {April},
	pages = {739{\textendash}749},
	author = {Martinez, Alfonso}
}
