Kiefer MC, Tucker JE, Joh R, Landsberg KE, Saltman D, Barr PJ (dezembro de 1991). «Identification of a second human subtilisin-like protease gene in the fes/fps region of chromosome 15». DNA and Cell Biology. 10 (10): 757–69. PMID1741956. doi:10.1089/dna.1991.10.757
Kiefer MC, Tucker JE, Joh R, Landsberg KE, Saltman D, Barr PJ (dezembro de 1991). «Identification of a second human subtilisin-like protease gene in the fes/fps region of chromosome 15». DNA and Cell Biology. 10 (10): 757–69. PMID1741956. doi:10.1089/dna.1991.10.757