text: Chapter 2
  Geographical entity Two-letter code Three-letter code
  —O—
  Oman OM OMN
  —P—
  Pakistan PK PAK
  Palau PW PLW
  Panama PA PAN
  Papua New Guinea PG PNG
  Paraguay PY PRY
  Peru PE PER
  Philippines PH PHL
  Pitcairn PN PCN
  Poland PL POL
  Portugal PT PRT
  Puerto Rico PR PRI
  —Q—
  Qatar QA QAT
  —R—
  Reunion RE REU
  Romania RO ROU
  Russian Federation RU RUS
  Rwanda RW RWA
  —S—
  Saint Helena SH SHL
  Saint Kitts and Nevis KN KNA
  Saint Lucia LC LCA
  Saint Pierre and Miquelon PM SPM
  Saint Vincent and the Grenadines VC VCT
  Samoa WS WSM
  San Marino SM SMR
  Sao Tome and Principe ST STP
  Saudi Arabia SA SAU
  Senegal SN SEN
  Serbia RS SRB
  Seychelles SC SYC
  Sierra Leone SL SLE
  Singapore SG SGP
  Slovakia SK SVK
  Slovenia SI SVN
  Solomon Islands SB SLB
  Somalia SO SOM
  South Africa ZA ZAF
  South Georgia and South Sandwich GS SGS
  Islands
  Spain ES ESP
  Sri Lanka LK LKA
  Sudan SD SDN