Forum Romanum
Outlines of Roman History: Rise of Antony and Octavius
In William Morey's 1901 textbook, he discusses the changes in Rome after Caesar's assassination, and the Second Triumvirate.
Franco Cavazzi
Roman empire.net: The Second Triumvirate
This site from the Roman-Empire.net provides information on the Second Triumvirate (Octavian, Antony, and Lepidus) and an explanation of what happened after Caesar's death.