Petykiewicz, J. On the Huygens principle for elastic media. (English) Zbl 0156.45504 Acta Phys. Pol. 30, 223-236 (1966). PDFBibTeX XMLCite \textit{J. Petykiewicz}, Acta Phys. Polon. 30, 223--236 (1966; Zbl 0156.45504)
Petykiewicz, J. On Kirchhoff diffraction theory for multipole radiation from Young’s point of view. (Part I - The dipole.). (English) Zbl 0137.23703 Acta Phys. Pol. 27, 3-11 (1965). PDFBibTeX XMLCite \textit{J. Petykiewicz}, Acta Phys. Polon. 27, 3--11 (1965; Zbl 0137.23703)