https://api.elsevier.com/content/article/pii/S0301421521001543doi:10.1016/j.enpol.2021.1122851-s2.0-S030142152100154310.1016/j.enpol.2021.112285S0301-4215(21)00154-3Comparative efficiency of green and conventional bonds pre- and during COVID-19: An asymmetric multifractal detrended fluctuation analysis Energy PolicyJournal030142152021-06-30June 20210falsefalse