[
  {
    "title": "Rpcop: Principal Curves of Oriented Points",
    "author": [
      {
        "given": "Kevin Michael",
        "family": "Frick",
        "role": {},
        "email": {},
        "comment": {}
      }
    ],
    "year": "2026",
    "note": "R package version 1.2.3",
    "url": "https://github.com/kmfrick/Rpcop"
  },
  {
    "title": "Principal Curves of Oriented Points: theoretical and computational improvements",
    "author": [
      {
        "given": "Pedro",
        "family": "Delicado",
        "role": {},
        "email": {},
        "comment": {}
      },
      {
        "given": "Mario",
        "family": "Huerta",
        "role": {},
        "email": {},
        "comment": {}
      }
    ],
    "journal": "Computational Statistics",
    "year": "2003",
    "volume": "18",
    "pages": "293--315",
    "doi": "10.1007/s001800300145"
  },
  {
    "title": "Another Look at Principal Curves and Surfaces",
    "author": [
      {
        "given": "Pedro",
        "family": "Delicado",
        "role": {},
        "email": {},
        "comment": {}
      }
    ],
    "journal": "Journal of Multivariate Analysis",
    "year": "2001",
    "volume": "77",
    "pages": "84--116",
    "doi": "10.1006/jmva.2000.1917"
  }
]