KALLIKORM, R.; TUVIK, P. Professor Reinhold Birkenfeldt 80 . Eesti Arst, [S. l.], 2014. DOI: 10.15157/ea.v0i0.11649. Disponível em: https://ojs.utlib.ee/index.php/EA/article/view/11649. Acesso em: 28 apr. 2025.