To avoid monotony, try to vary both the language and the placement of your signal phrases.
Model signal phrases
In the words of historian James M. McPherson, “…”1
As Dudley Taylor Cornish has argued, “…”2
In a letter to his wife, a Confederate soldier who witnessed the massacre wrote that “…”3
“…,” claims Benjamin Quarles.4
“…,” writes Albert Castel, “…”5
Shelby Foote offers an intriguing interpretation: “…”6
Verbs in signal phrases
| admits | compares | insists | rejects |
| agrees | confirms | notes | reports |
| argues | contends | observes | responds |
| asserts | declares | points out | suggests |
| believes | denies | reasons | thinks |
| claims | emphasizes | refutes | writes |