Pál Zakar
Unknown Author
G. D. Kkreítser
L. A. Johnson
Pál Zakar
Meyer, R. F.
Karl Ziegs
Richard Langlois
International Asphalt Congress (2nd 1954 Rome)
Johan Philip Pfeiffer
Bonnie L Crysdale
Semen Romanovich Sergienko
Daniil Vasilʹevich Zhabrev
T. McNally
Galina Petrovna Kajukova
E. J. Hoffman
Aksenov, A. A. doktor geologo-mineralogicheskikh nauk.
Gary V. Wilson