^Michael Szpir (May–June 2001). "Bart Bok's Black Blobs". American Scientist. Diarsipkan dari versi asli tanggal 2017-04-24. Diakses tanggal 2008-11-19. Bok globules such as Barnard 68 are only about half a light-year across and weigh in at about two solar masses
^Clemens, Dan P.; Yun, João Lin; Meyer, Mark H. (March 1991). "BOK globules and small molecular clouds – Deep IRAS photometry and (C-12)O spectroscopy". Astrophysical Journal Supplement. 75: 877. Bibcode:1991ApJS...75..877C. doi:10.1086/191552.
^Launhardt, R.; Sargent, A. I.; Henning, T.; Zylka, R.; Zinnecker, H. (10–15 April 2000). "Binary and multiple star formation in Bok globules". Birth and Evolution of Binary Stars, Poster Proceedings of IAU Symposium No. 200 on The Formation of Binary Stars. Potsdam, Germany: Bo Reipurth and Hans Zinnecker. hlm. 103. Bibcode:2000IAUS..200P.103L.