I returned to my blanket and again was just closing my eyes when the unexpected sound of gregorian chant made me sit up.
"My Home In The Field of Honor"
Frances Wilson Huard
The Julian and gregorian calendars are frequently represented by the abbreviations O. S. and N. S., old style, new style, and as the older historical dates are usually expressed in O. S., it is sometimes convenient to transform a date from the one calendar to the other.
"A Text-Book of Astronomy"
George C. Comstock
This was the 23rd of April, Old Style, which corresponds with the 3rd of May in the gregorian calendar.
"The South American Republics Part I of II"
Thomas C. Dawson