@article{CTT100626961,
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  title = {Crystal Structure and Properties of Phosphate PbCu2(PO4)2 with Spin-Singlet Ground State},
  journal = {Phys. Rev., 73},
  year = 2006,
}

@article{CTT100626957,
  author = {Kaji and S. Okubo and H. Ohta and Yuhji Inagaki and A.A. Belik and M. Azuma and M. Takano},
  title = {High Field ESR Measurements of Spin Gap System MCu2(PO4)2},
  journal = {J. Phys. & Chem. Solids,},
  year = 2005,
}