T.  Kato, ?Taxonomical studies on the Hypericum pseudopetiolatum complex: 4. Allozyme divergence and phylogenetic inference.?, J. Fac. Sci. Univ. Tokyo, Bot., vol. 14, pp. 341-368 (1990) - maps., 1990.

T.  Kato, ?Taxonomical studies on the Hypericum pseudopetiolatum complex 1. Geographical differentiation in the Japan Archipelago.?, Bot. Mag. Tokyo, vol. 98, pp. 359-370 (1985) - illus., maps., 1985.

T.  Kato, ?Taxonomical studies on the Hypericum pseudopetiolatum complex: 2. Natural hybridizations in Kyushu.?, Bull. Nation. Sci. Mus., B (Tokyo), vol. 12, pp. 139-149 (1986) - map., 1986.

T.  Kato, ?Does Hypericum penthorodes Kaidz. really exist as a species??, Ann. Tsukuba Bot. Gard., vol. no.5, pp. 31-39 (1986) -, 1986.

T.  Kato, ?Taxonomical studies on the Hypericum pseudopetiolatum complex: 3. Taxonomy.?, Bull. Nation. Sci. Mus., B (Tokyo), vol. 13, pp. 69-80 (1987) - illus., 1987.

T.  Kato, ?Allozyme variation in Hypericum pseudopetiolatum R.Keller  (Hypericaceae) in Hokkaido and Tohoku district.?, Mem. Nation. Sci. Mus. (Tokyo), vol. no.21, pp. 81-85 (1988) - maps., 1988.