HSF Final Report: Seeking a Human Spaceflight Program Worthy of a Great NationАрхивирано на сајту Wayback Machine (16. фебруар 2019), October 2009, Review of U.S. Human Spaceflight Plans Committee. стр. 64-66: "5.2.1 The Need for Heavy Lift ... require a “super heavy-lift” launch vehicle ... range of 25 to 40 mt, setting a notional lower limit on the size of the super heavy-lift launch vehicle if refueling is available ... this strongly favors a minimum heavy-lift capacity of roughly 50 mt ..."
Hill, James V. H. (април 1999), „Getting to Low Earth Orbit”, Space Future, Архивирано из оригинала 2012-03-19. г., Приступљено 2012-03-18.CS1 одржавање: Формат датума (веза)
Hill, James V. H. (април 1999), „Getting to Low Earth Orbit”, Space Future, Архивирано из оригинала 2012-03-19. г., Приступљено 2012-03-18.CS1 одржавање: Формат датума (веза)
HSF Final Report: Seeking a Human Spaceflight Program Worthy of a Great NationАрхивирано на сајту Wayback Machine (16. фебруар 2019), October 2009, Review of U.S. Human Spaceflight Plans Committee. стр. 64-66: "5.2.1 The Need for Heavy Lift ... require a “super heavy-lift” launch vehicle ... range of 25 to 40 mt, setting a notional lower limit on the size of the super heavy-lift launch vehicle if refueling is available ... this strongly favors a minimum heavy-lift capacity of roughly 50 mt ..."