@article{TM2_2008_XI_1_a2,
     author = {Milan Janji\'c},
     title = {Geometrical definition of {Pi} and its approximations by nested radicals},
     journal = {The Teaching of Mathematics},
     pages = {25 },
     publisher = {mathdoc},
     volume = {XI},
     number = {1},
     year = {2008},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TM2_2008_XI_1_a2/}
}