text: The following research papers from IUPAC are in pdf format:
  *[https://www.iupac.org/publications/pac/1998/pdf/7006x1277.pdf Biodegradable hydrogels for bone regeneration through growth factor release]
  *[https://www.iupac.org/publications/pac/2004/pdf/7607x1295.pdf Development of acid-sensitive copolymer micelles for drug delivery]