Note: "俄罗斯在两年前曾向越南交付了两艘先进的猎豹级护卫舰."
(a) Vietnam People's Navy http://en.wikipedia.org/wiki/Vietnam_People's_Navy
(section 4 Fleet: Gepard 3.9 class frigates, 2 in active duty (2 more under construction))
(b) Gepard-class frigate http://en.wikipedia.org/wiki/Gepard-class_frigate
(Russian Gepard ("Cheetah") class frigates (Project 1166.1); Built 1991- ; The Vietnam People's Navy received in March and August 2011 two Gepard 3.9 class frigates ordered in 2006, built in Russia at Tatarstan's Gorky Shipbuilding Plant)
(c) Construction of Two Corvettes for Vietnamese Navy Goes on as Scheduled - Rosoboronexport. Itar-Tass, June 5, 2013 http://www.itar-tass.com/en/c467/798014.html