Speas, R. D., Smith, M. H., & Schmidt, H. P. (1967). Cost/benefit analysis for all-weather landing systems (AWLS) category II and III: Final report. R. Dixon Speas Associates.
Chicago-viite (17. p.)Speas, Robert Dixon, M. H. Smith, ja Harry P. Schmidt. Cost/benefit Analysis for All-weather Landing Systems (AWLS) Category II and III: Final Report. Manhasset, N.Y.: R. Dixon Speas Associates, 1967.
MLA-viite (8. p.)Speas, Robert Dixon, et al. Cost/benefit Analysis for All-weather Landing Systems (AWLS) Category II and III: Final Report. R. Dixon Speas Associates, 1967.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.