[
 {
  "key": "gps-alpha",
  "value": "0.19e-5",
  "sigma": "2.48e-5",
  "source": "Delva et al., PRL 121, 231101 (Galileo 5 and 6, redshift law over an eccentric GNSS orbit), experiments-2 E1",
  "year": "2018"
 },
 {
  "key": "pr",
  "value": "2.45005e-15",
  "sigma": "1.8639e-17",
  "source": "Pound and Snider, Phys Rev 140, B788 (0.9990 +/- 0.0076 of 2.4525e-15)",
  "year": "1965"
 },
 {
  "key": "hk-east",
  "value": "-59",
  "sigma": "10",
  "source": "Hafele and Keating, Science 177, 168",
  "year": "1972"
 },
 {
  "key": "hk-west",
  "value": "273",
  "sigma": "7",
  "source": "Hafele and Keating, Science 177, 168",
  "year": "1972"
 },
 {
  "key": "gamma-cassini",
  "value": "2.1e-5",
  "sigma": "2.3e-5",
  "source": "Bertotti, Iess and Tortora, Nature 425, 374",
  "year": "2003"
 },
 {
  "key": "gamma-vlbi",
  "value": "-0.8e-4",
  "sigma": "1.2e-4",
  "source": "Lambert and Le Poncin-Lafitte, A&A 529, A70",
  "year": "2011"
 },
 {
  "key": "mercury",
  "value": "42.98",
  "sigma": "0.04",
  "source": "Park et al. 2017 (record figure, experiments-2 E7)",
  "year": "2017"
 },
 {
  "key": "muon",
  "value": "64.3782",
  "sigma": "0.0259",
  "source": "Bailey et al., Nature 268, 301 (credibility-weighted, experiments-2 E4)",
  "year": "1977"
 },
 {
  "key": "ht",
  "value": "-2.398e-12",
  "sigma": "0.004e-12",
  "source": "Weisberg and Huang, ApJ 829, 55 (intrinsic)",
  "year": "2016"
 },
 {
  "key": "neutron",
  "value": "716.8",
  "sigma": "3.8",
  "source": "Rauch, Wilfing, Bauspiess and Bonse, Z Phys B 29, 281 (experiments-2 E6)",
  "year": "1978"
 },
 {
  "key": "neff",
  "value": "2.99",
  "sigma": "0.17",
  "source": "Planck 2018 VI",
  "year": "2018"
 },
 {
  "key": "radium",
  "value": "3.7e10",
  "sigma": "0.074e10",
  "source": "the radium standard defining the curie (1910, 1930), 2 %",
  "year": "1930"
 },
 {
  "key": "yp",
  "value": "0.2453",
  "sigma": "0.0034",
  "source": "Aver et al., JCAP 03, 027 (helium-4 from metal-poor H II regions)",
  "year": "2021"
 }
]