Henn, R. W. (2003). AUA guidelines for backfilling and contact grouting of tunnels and shafts. Reston, VA: American Society of Civil Engineers.
Παραπομπή Chicago StyleHenn, Raymond W. AUA Guidelines for Backfilling and Contact Grouting of Tunnels and Shafts. Reston, VA: American Society of Civil Engineers, 2003.
Παραπομπή MLAHenn, Raymond W. AUA Guidelines for Backfilling and Contact Grouting of Tunnels and Shafts. Reston, VA: American Society of Civil Engineers, 2003.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.