20ポンドアームストロング砲
Treatise on the construction and manufacture of ordnance in the British service. War Office, UK, 1877
Text Book of Gunnery, 1887. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HARRISON AND SONS, ST. MARTIN'S LANE
Alexander Lyman Holley, "A treatise on Ordnance and Armor" published by D Van Nostrand, New York, 1865
Lieutenant-Colonel C H Owen R.A., "The principles and practice of modern artillery". published by John Murray, London, 1873
20ポンドアームストロング砲(Armstrong Breech Loading 20 pounder gunまたはRBL 20 pounder)は1859年から配備された口径3.75インチの後装式施条砲。