Idris, A.M.; Prokopczyk, B.; Hoffmann, D. (November 1994). "Toombak: A Major Risk Factor for Cancer of the Oral Cavity in Sudan". Preventive Medicine. 23 (6): 832–839. doi:10.1006/pmed.1994.1141. PMID7855117.
Idris, A. M; Ibrahim, S. O; Vasstrand, E. N; Johannessen, A. C; Lillehaug, J. R; Magnusson, B; Wallström, M; Hirsch, J. -M; Nilsen, R (1 November 1998). "The Swedish Snus and the Sudanese Toombak: are they different?". Oral Oncology. 34 (6): 558–566. doi:10.1016/S1368-8375(98)00047-5. hdl:1956/2153. PMID9930371.
Specht, Alexandre; de Paula-Moraes, Silvana V.; Sosa-Gómez, Daniel R. (2015). "Host plants of Chrysodeixis includens (Walker) (Lepidoptera, Noctuidae, Plusiinae)". Revista Brasileira de Entomologia. 59 (4): 343–345. Bibcode:2015RvBrE..59..343S. doi:10.1016/j.rbe.2015.09.002.
Idris, A. M; Ibrahim, S. O; Vasstrand, E. N; Johannessen, A. C; Lillehaug, J. R; Magnusson, B; Wallström, M; Hirsch, J. -M; Nilsen, R (1 November 1998). "The Swedish Snus and the Sudanese Toombak: are they different?". Oral Oncology. 34 (6): 558–566. doi:10.1016/S1368-8375(98)00047-5. hdl:1956/2153. PMID9930371.
Specht, Alexandre; de Paula-Moraes, Silvana V.; Sosa-Gómez, Daniel R. (2015). "Host plants of Chrysodeixis includens (Walker) (Lepidoptera, Noctuidae, Plusiinae)". Revista Brasileira de Entomologia. 59 (4): 343–345. Bibcode:2015RvBrE..59..343S. doi:10.1016/j.rbe.2015.09.002.
Idris, A.M.; Prokopczyk, B.; Hoffmann, D. (November 1994). "Toombak: A Major Risk Factor for Cancer of the Oral Cavity in Sudan". Preventive Medicine. 23 (6): 832–839. doi:10.1006/pmed.1994.1141. PMID7855117.
Idris, A. M; Ibrahim, S. O; Vasstrand, E. N; Johannessen, A. C; Lillehaug, J. R; Magnusson, B; Wallström, M; Hirsch, J. -M; Nilsen, R (1 November 1998). "The Swedish Snus and the Sudanese Toombak: are they different?". Oral Oncology. 34 (6): 558–566. doi:10.1016/S1368-8375(98)00047-5. hdl:1956/2153. PMID9930371.