Bartaševičius, Algimantas, Petras Ilgakojis, and Stanislovas Merkevičius. 2004. “Mathematical Modeling of the Self Vibration Frequencies of Mechanical Frames of Controls Rigs”. Lietuvos Matematikos Rinkinys 44 (spec.): 23–34. https://doi.org/10.15388/LMR.2004.31742.