M.  Langourov, Lazarov, S., Stoev, P., Guéorguiev, B., Deltshev, C., Petrov, B., Andreev, S., Simov, N., Bekchiev, R., Antonova, V., Ljubomirov, T., Dedov, I., and Georgiev, D., ?New and interesting records of the MSS and cave fauna of Vitosha Mt., Bulgaria?, Balkan Speleological Conference ?Sofia?2014?, Sofia, Bulgaria, 28 ? 30 March 2014. Caving Club ?Helictite? ? Sofia, pp. 66-76, 2014.

R.  Kostova, Lazarov, S., Bekchiev, R., Goranov, S., Simov, N., and Beshkov, S., Soil and cave invertebrates from the village Gintsi area. Sofia: Association of Speleoclubs in Sofia, 2016, p. 116.

M.  Langourov, Simov, N., Bekchiev, R., Chobanov, D., Antonova, V., and Dedov, I., ?Inventory of selected Groups of invertebrates in sedge and reedbeds not associated with open waters in Bulgaria?, Acta Zoologica Bulgarica, vol. 70, no. 4, pp. 487-500, 2018.

R.  Bekchiev, ?The Pselaphinae (Coleoptera: Staphylinidae) of Bulgaria, version 1.2.?, 2016. [Online]. Available: http://pselaphinae-bg.myspecies.info. [Accessed: 2016-01-10].

R.  Bekchiev, ?Description of a new species of Trimium Aubé, 1833 (Staphylinidae: Pselaphinae) from Bulgaria and Greece?, Acta zoologica bulgarica, vol. 65, no. 3, p. 289?291, 2013.

R.  Bekchiev, ?Faunistic review and description of a new species of Pselaphinae (Coleoptera:Staphylinidae) from the Strandzha Mountains (Bulgaria and Turkey)?, Turkish Journal of Zoology, vol. 37, no. 4, pp. 431-440, 2013.

R.  Bekchiev, ?The subfamily Pselaphinae (Coleoptera: Staphylinidae) of southwestern Bulgaria II: Belasitsa Mts.?, Biologia (Bratislava), vol. 66, no. 3, pp. 506-508, 2011.

R.  Bekchiev, ?The subfamily Pselaphinae (Coleoptera: Staphylinidae) of southwestern Bulgaria. I?, Historia Naturalis Bulgarica, vol. 19, pp. 51-71, 2008.

R.  Bekchiev, ?Variability in the structure of the aedeagus of Dicentrius rousi Besuchet 1999 ( Coleoptera: Staphylinidae: Pselaphinae)?, Acta Zoologica Bulgarica, vol. Supplementum 2, pp. 25-28, 2008.

R.  Bekchiev, ?A study of the Pselaphinae (Coleoptera, Staphylinidae) in the Rhodope Mountains (Bulgaria)?, in Biodiversity of Bulgaria 4. Biodiversity of Western Rhodopes (Bulgaria and Greece) II., P.  Beron, Ed. Sofia: Pensoft Publishers & National Museum of Natural History, Bulgarian Academy of Sciences, 2011, p. 267?278.

R.  Bekchiev and Brachat, V., ?Revision of the genus Delenda Croissandeau, 1891 (Coleoptera: Staphylinidae: Pselaphinae)?, Zootaxa, vol. 3765, no. 6, pp. 583?592, 2014.

R.  Bekchiev and Shishiniova, M., ?A contribution to the Pselaphinae fauna (Coleoptera: Staphylinidae) of the Vitosha Mountain?, Acta Zoologica Bulgarica, vol. 59, no. 1, pp. 33-39, 2007.

C.  Besuchet and Bekchiev, R., ?Description d'un nouveau Batrisodes de la Bulgarie (Coleoptera: Staphylinidae: Pselaphinae)?, Historia Naturalis Bulgarica, vol. 18, pp. 75-80, 2007.

R.  Bekchiev and Guéorguiev, B., ?First purposive study of beetles (Coleoptera) from endogean environments in Bulgaria: collection sites and preliminary results?, Biodiversity Journal, vol. 6, no. 1, pp. 327?340, 2015.

P.  Hlavá?, Bekchiev, R., R??i?ka, J., and Lackner, T., ?Contribution to the knowledge of myrmecophilous beetles (Coleoptera) of Bulgaria?, Acta Societatis Zoologicae Bohemicae, vol. 71, no. 2, pp. 131-136, 2007.

R.  Bekchiev, ?Faunistical research on Pselaphinae fauna (Coleoptera: Staphylinidae) in several regions of south-west Bulgaria?, Sofia University 'St. Climent Ohridski", Sofia, 2007.