• Emeriitprofessor Peep Christjanson 70Mente et Manu2010 / lk. 2 : portr https://www.ester.ee/record=b1242496*est
  • Peep Christjanson 60Tehnikaülikool2000 / lk. 16 : portr https://artiklid.elnet.ee/record=b1660999*est