@article{TM2_2018_XXI_2_a1,
     author = {Yuanhong Zhi},
     title = {A greatest common divisor identity},
     journal = {The Teaching of Mathematics},
     pages = {73 },
     year = {2018},
     volume = {XXI},
     number = {2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TM2_2018_XXI_2_a1/}
}