Pokorny, Julius (2005) [1959]. "per-3, per-g-". indogermanisches etymologisches woerterbuch. Leiden: Leiden University, the IEED-project. pp. 818–819. Archived from the original on August 9, 2011.
Pokorny, Julius (2005) [1959]. "per-3, per-g-". indogermanisches etymologisches woerterbuch. Leiden: Leiden University, the IEED-project. pp. 818–819. Archived from the original on August 9, 2011.