The notation Old Style or (OS) is sometimes used to indicate a date in the Julian Calendar (which is used by churches on the "Old Calendar"). The notation New Style or (NS), indicates a date in the Revised Julian calendar (which is used by churches on the "New Calendar".
"At Lambesa, in Numidia, the birthday of the holy martyrs Marian, lector, and James, deacon. The former, after having successfully endured vexations for the confession of Christ, in the persecution of Decius, was again arrested with his illustrious companion, and both being subjected to severe and cruel torments, during which they were twice miraculously comforted from heaven, finally fell by the sword with many others."[6]
"At Saintes, blessed Eutropius, bishop and martyr, who was consecrated bishop and sent to Gaul by St. Clement. After preaching for many years, he had his skull crushed for bearing testimony to Christ, and thus gained a victory by his death."[6]
"At Cordova, the holy martyrs Amator, priest, Peter, monk, and Lewis."[6] They are referred to as "Amator, Peter and Louis" (+855) in Western sources.[11][19]
Elias, Paul and Isidore (SS.) MM. (April 17) (9th century):
"St. Elias was a priest venerable for age and virtue, who together with Paul and Isidore, two young Christians, his spiritual children, suffered for Christ (A.D. 856) at Cordova in Spain in the persecution under the Caliph Mohammed. St. Eulogius makes special mention of them in his History of the Times."[21]
The Roman Martyrology. Transl. by the Archbishop of Baltimore. Last Edition, According to the Copy Printed at Rome in 1914. Revised Edition, with the Imprimatur of His Eminence Cardinal Gibbons. Baltimore: John Murphy Company, 1916. pp.121-122.
Rev. Sabine Baring-Gould (M.A.). "S. Donatus, B. of Evrœa. (About A.D. 387.)" In: The Lives of the Saints. Volume the Fourth: April. London: John C. Nimmo, 1897. p.373.
Rev. Sabine Baring-Gould (M.A.). "SS. Marian, James, and Comp., MM. (About A.D. 259.)" In: The Lives of the Saints. Volume the Fourth: April. London: John C. Nimmo, 1897. pp.371-373.
"Elias, Pual, and Isidore (SS.) MM. (April 17)." In: The Benedictine Monks of St. Augustine's Abbey, Ramsgate (Comp.). The Book of Saints: A Dictionary of Servants of God Canonised by the Catholic Church: Extracted from the Roman & Other Martyrologies. London: A. & C. Black, Ltd., 1921. p.91.
Rev. Sabine Baring-Gould (M.A.). "S. Forannan, Ab. of Waulsor. (A.D. 982.)" In: The Lives of the Saints. Volume the Fourth: April. London: John C. Nimmo, 1897. pp.376-377.
Dr. Alexander Roman. AprilArchived 2017-12-05 at the Wayback Machine. Calendar of Ukrainian Orthodox Saints (Ukrainian Orthodoxy - Українське Православ'я).
April 30. Latin Saints of the Orthodox Patriarchate of Rome.
The Roman Martyrology. Transl. by the Archbishop of Baltimore. Last Edition, According to the Copy Printed at Rome in 1914. Revised Edition, with the Imprimatur of His Eminence Cardinal Gibbons. Baltimore: John Murphy Company, 1916. pp.121-122.
(in Greek) Συναξαριστής. 30 Απριλίου. Ecclesia.gr. (H Εκκλησία της Ελλάδος).
Russian Sources
(in Russian)13 мая (30 апреля). Православная Энциклопедия под редакцией Патриарха Московского и всея Руси Кирилла (электронная версия). (Orthodox Encyclopedia - Pravenc.ru).