A. C. Rachmawati, H. Purnaweni, and P. E. Soesanta, “Economic Valuation of Senjoyo Spring Nature Tourism Using Travel Cost Method and Willingness to Pay : JEL Classification: Q51; Q26; Z32; H41; R11.”, JLB, vol. 7, no. 4, pp. 884-903, Sep. 2026.