Donald, E., and D. Andreas. “Analysis and Dynamic Behavior of Portal Structures Due to Reciprocating Machine”. IJTI International Journal of Transportation and Infrastructure EISSN 2597-4769 PISSN 2597-4734, Vol. 3, no. 2, July 2020, p. 120-`129, doi:10.29138/ijti.v3i2.1063.