Symposium on Rapid Excavation Sacramento, Calif, Sacramento State College. School of Engineering, & Hartman, H. L. (1969). Progress toward goals: Proceedings of the II symposium on rapid excavations, October 16-17, 1969. Sacramento State College.
Lua i Stíl Chicago (17ú heag.)Symposium on Rapid Excavation Sacramento, Calif, Sacramento State College. School of Engineering, agus Howard L. Hartman. Progress Toward Goals: Proceedings of the II Symposium on Rapid Excavations, October 16-17, 1969. Sacramento: Sacramento State College, 1969.
Lua MLA (8ú heag.)Symposium on Rapid Excavation Sacramento, Calif, et al. Progress Toward Goals: Proceedings of the II Symposium on Rapid Excavations, October 16-17, 1969. Sacramento State College, 1969.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.