Steel, Duncan. Marking time: the epic quest to invent the perfect calendar. John Wiley & Sons,2000,p.113. ISBN 978-0-471-29827-4.«In the B.C./A.D. scheme there is no year zero. After 31 December 1 BC came 1 January AD 1. ... If you object to that no-year-zero scheme, then don't use it: use the astronomer's counting scheme, with negative year numbers.»
«Null values and the nullable type»,12 desembre 2018. Arxivat de l'original el 23 novembre 2021.[Consulta: 23 novembre 2021].«In regard to services, sending a null value as an argument in a remote service call means that no data is sent. Because the receiving parameter is nullable, the receiving function creates a new, uninitialized value for the missing data then passes it to the requested service function.»
«Null values and the nullable type»,12 desembre 2018. Arxivat de l'original el 23 novembre 2021.[Consulta: 23 novembre 2021].«In regard to services, sending a null value as an argument in a remote service call means that no data is sent. Because the receiving parameter is nullable, the receiving function creates a new, uninitialized value for the missing data then passes it to the requested service function.»