BioStor
 | Materials toward a monograph of the genus Verbena. XXVI H N Moldenke (1965) Phytologia 11: 219-287 |
 | Materials toward a monograph of the genus Verbena. XXIX H N Moldenke (1965) Phytologia 11: 435-507 |
 | Additional notes on the genus Verbena. VI H N Moldenke (1968) Phytologia 16: 87-106 |
 | Additional notes on the genus Verbena. XII H N Moldenke (1972) Phytologia 23: 257-303 |
 | Additional notes on the genus Verbena. XXIII H N Moldenke (1975) Phytologia 30: 129-180 |
 | Additional notes on the genus Verbena. XXV H N Moldenke (1977) Phytologia 36: 216-250 |