^Yoshiharu Doi, Masao Kunioka, Yoshiyuki Nakamura, Kazuo Soga. Nuclear magnetic resonance studies on unusual bacterial copolyesters of 3-hydroxybutyrate and 4-hydroxybutyrate. Macromolecules. 1988, 21 (9): 2722–2727. doi:10.1021/ma00187a012.
^ Dieter Seebach, Albert K. Beck, Richard Breitschuh, and Kurt Job "Direct Degradation of the Biopolymer Poly[(R)-3-Hydroxybutrric Acid to (R)-3-Hydroxybutanoic Acid and Its Methyl Ester" Org. Synth. 1993, 71, 39. doi:10.15227/orgsyn.071.0039