R K Ranjan
"An upper bound solution for closed die forging of sintered polygon".
Tamkang J. of Sci. and Engineering, Taiwan, ROC,
vol: 6,
No. 4
Jun. 2003,
pp: 207-216,
https://scholar9.com/publication-detail/an-upper-bound-solution-for-closed-die-forging-of-5230