1SAHOO 2017 and DMITRIEV 2003 are not direct measurements of the proton electric dipole moment. They use theory to calculate this limit from the limit on the electric dipole moment of the ${}^{199}\mathrm {Hg}$ atom.
2
This WILKENING 1984 value includes a finite-size effect and a magnetic effect.
3
This WILKENING 1984 value is more cautious than the other and excludes the finite-size effect, which relies on uncertain nuclear integrals.
Improved Limits on the Hadronic and Semi-Hadronic $\mathit CP$ Violating Parameters and Role of a Dark Force Carrier in the Electric Dipole Moment of ${}^{199}\mathrm {Hg}$
DMITRIEV
2003
PRL 91 212303
Schiff Moment of the Mercury Nucleus and the Proton Dipole Moment
CHO
1989
PRL 63 2559
Tenfold Improvement of Limits on $\mathit T$ Violation in Thallium Fluoride
DZUBA
1985
PL 154B 93
Bounds on Electric Dipole Moments and $\mathit T$ Violating Weak Interactions of the Nucleons
WILKENING
1984
PR A29 425
Search for $\mathit P$ and $\mathit T$ Violations in the Hyperfine Structure of Thallium Fluoride
HARRISON
1969
PRL 22 1263
Experimental Limit on the Proton Electric Dipole Moment