Elliott J C, Holcomb D W, Young R A
Calcif Tissue Int. 1985 Jul;37(4):372-5. doi: 10.1007/BF02553704.
About 11 +/- 1% of the carbonate ions in a human tooth enamel specimen (dense fraction, sp. g. greater than 2.95) were found to be in the A-sites, replacing hydroxyl ions. The determination was made with a difference infrared spectrometry technique utilizing both tooth enamel and a reconstituted biological apatite with a known amount of replacement of hydroxyl by carbonate ions.
在人类牙釉质标本（致密部分，比重超过2.95）中，约11±1%的碳酸根离子被发现位于A位，取代了氢氧根离子。该测定是使用差示红外光谱技术进行的，该技术同时使用了牙釉质和一种重构的生物磷灰石，其中碳酸根离子对氢氧根离子的取代量是已知的。
