1. Kostyuchenko, O.I., Chemical Composition and Pharmacological Properties of Stachys L, Rastit. Resur., 1983, vol. 19, no. 3, pp. 407–413.
2. Kartsev, V.G., Stepanichenko, N.N., and Auelbekov, S.A., Chemical Composition and Pharmacological Properties of Stachys Plants, Khim. Prirod. Soed., 1994, vol. 30, no. 6, pp. 699–709.
3. Liventaal, E.I., The Use of Perennial Flowers for Settlement Gardening, Vopr. Dekor. Sadovod. Landshaftoved., 1986, pp. 5–12.
4. Bentham, G., Labiatarum genera et species, 1832–1836.
5. Bentham, G. and Hooker, J.D., Genera plantarum, 1876.