Asian stock markets have rallied at the end of the trading week. The move came after a slight rebound in oil prices, and hints that the European Central Bank (ECB) may act to stimulate the eurozone economy. European indices have also opened higher. It follows a slump in stock markets earlier in the week on concerns about oil, China's economy, and global growth. Danny Cox of stockbroker Hargreaves Lansdown, says the ECB's chief has played a role in boosting stocks.