Hubbard & Simmons 2008, p. viii. Hubbard, Kenneth; Simmons, Michael (2008). Dropping Britain's first H-bomb : the story of Operation Grapple 1957/58. Barnsley, South Yorkshire: Pen & Sword Aviation. ISBN978-1-84415-747-1. OCLC436867016.
Hubbard & Simmons 2008, pp. 1–3. Hubbard, Kenneth; Simmons, Michael (2008). Dropping Britain's first H-bomb : the story of Operation Grapple 1957/58. Barnsley, South Yorkshire: Pen & Sword Aviation. ISBN978-1-84415-747-1. OCLC436867016.
Hubbard & Simmons 2008, p. 5. Hubbard, Kenneth; Simmons, Michael (2008). Dropping Britain's first H-bomb : the story of Operation Grapple 1957/58. Barnsley, South Yorkshire: Pen & Sword Aviation. ISBN978-1-84415-747-1. OCLC436867016.
Hubbard & Simmons 2008, p. 20. Hubbard, Kenneth; Simmons, Michael (2008). Dropping Britain's first H-bomb : the story of Operation Grapple 1957/58. Barnsley, South Yorkshire: Pen & Sword Aviation. ISBN978-1-84415-747-1. OCLC436867016.
Hubbard & Simmons 2008, pp. 40–41. Hubbard, Kenneth; Simmons, Michael (2008). Dropping Britain's first H-bomb : the story of Operation Grapple 1957/58. Barnsley, South Yorkshire: Pen & Sword Aviation. ISBN978-1-84415-747-1. OCLC436867016.
Hubbard & Simmons 2008, p. 43. Hubbard, Kenneth; Simmons, Michael (2008). Dropping Britain's first H-bomb : the story of Operation Grapple 1957/58. Barnsley, South Yorkshire: Pen & Sword Aviation. ISBN978-1-84415-747-1. OCLC436867016.
Hubbard & Simmons 2008, p. 120. Hubbard, Kenneth; Simmons, Michael (2008). Dropping Britain's first H-bomb : the story of Operation Grapple 1957/58. Barnsley, South Yorkshire: Pen & Sword Aviation. ISBN978-1-84415-747-1. OCLC436867016.
Hubbard & Simmons 2008, p. ix. Hubbard, Kenneth; Simmons, Michael (2008). Dropping Britain's first H-bomb : the story of Operation Grapple 1957/58. Barnsley, South Yorkshire: Pen & Sword Aviation. ISBN978-1-84415-747-1. OCLC436867016.
Hubbard & Simmons 2008, p. iv. Hubbard, Kenneth; Simmons, Michael (2008). Dropping Britain's first H-bomb : the story of Operation Grapple 1957/58. Barnsley, South Yorkshire: Pen & Sword Aviation. ISBN978-1-84415-747-1. OCLC436867016.