Cox, J. D. (1982). „Notation for states and processes, significance of the word standard in chemical thermodynamics, and remarks on commonly tabulated forms of thermodynamic functions”. Pure and Applied Chemistry. 54 (6): 1239. doi:10.1351/pac198254061239.
Standard Pressure IUPAC defines the "standard pressure" as being 105 Pa (which amounts to 1 bar).
mcgraw-hill.com
highered.mcgraw-hill.com
Appendix 1: Property Tables and Charts (SI Units), Scroll down to Table A-5 and read the temperature value of 99.61 °C at a pressure of 100 kPa (1 bar). Obtained from McGraw-Hill's Higher Education website.