Top design study on sustainable development of highway in China 并列题名：Top design study on sustainable development of highway in China Study on sustainable development of coal industry dStudy on sustainable development of tourism industry 并列题名：Study on sustainable development of coal industry an overview study of sustainable development in European Union Exploring the sustainable development of high-density cities 并列题名：Study on the sustainable development of highway transportation 并列题名：Study on sustainable development of mineral resources in China Research on sustainable development of aging society