Blumenkrantz, N.; Asboe-Hansen, G. (1975). "An assay for hydroxyproline and proline on one sample and a simplified method for hydroxyproline". Analytical Biochemistry. 63 (2): 331–340. doi:10.1016/0003-2697(75)90354-1. PMID1122021.
Maruyama, S; Miyoshi, S; Nomura, G; Suzuki, M; Tanaka, H; Maeda, H (1993). "Specificity for various imino-acid-residues of a proline-specific dipeptidylcarboxypeptidase from a Streptomyces species". Biochim Biophys Acta. 1162 (1–2): 72–76. doi:10.1016/0167-4838(93)90129-f. PMID8448197.
Blumenkrantz, N.; Asboe-Hansen, G. (1975). "An assay for hydroxyproline and proline on one sample and a simplified method for hydroxyproline". Analytical Biochemistry. 63 (2): 331–340. doi:10.1016/0003-2697(75)90354-1. PMID1122021.
Maruyama, S; Miyoshi, S; Nomura, G; Suzuki, M; Tanaka, H; Maeda, H (1993). "Specificity for various imino-acid-residues of a proline-specific dipeptidylcarboxypeptidase from a Streptomyces species". Biochim Biophys Acta. 1162 (1–2): 72–76. doi:10.1016/0167-4838(93)90129-f. PMID8448197.