Havil, J. (2005). GAMMA: EXploring Euler`s Constant (1st.). ICFAI University Press.
芝加哥风格引文Havil, Julian. GAMMA: EXploring Euler`s Constant. 1st. Hyderabad: ICFAI University Press, 2005.
MLA引文Havil, Julian. GAMMA: EXploring Euler`s Constant. 1st. ICFAI University Press, 2005.
警告：这些引文格式不一定是100％准确.